diff options
Diffstat (limited to 'src/VBox/NetworkServices/NAT/pxtcp.c')
| -rw-r--r-- | src/VBox/NetworkServices/NAT/pxtcp.c | 2392 |
1 files changed, 2392 insertions, 0 deletions
diff --git a/src/VBox/NetworkServices/NAT/pxtcp.c b/src/VBox/NetworkServices/NAT/pxtcp.c new file mode 100644 index 00000000..8bdc5581 --- /dev/null +++ b/src/VBox/NetworkServices/NAT/pxtcp.c @@ -0,0 +1,2392 @@ +/* -*- indent-tabs-mode: nil; -*- */ +#include "winutils.h" + +#include "pxtcp.h" + +#include "proxy.h" +#include "proxy_pollmgr.h" +#include "pxremap.h" +#include "portfwd.h" /* fwspec */ + +#ifndef RT_OS_WINDOWS +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/ioctl.h> +#ifdef RT_OS_SOLARIS +#include <sys/filio.h> /* FIONREAD is BSD'ism */ +#endif +#include <stdlib.h> +#include <stdint.h> +#include <stdio.h> +#include <string.h> +#include <poll.h> + +#include <err.h> /* BSD'ism */ +#else +#include <stdlib.h> +#include <stdio.h> +#include <string.h> + +#include <iprt/stdint.h> +#include "winpoll.h" +#endif + +#include "lwip/opt.h" + +#include "lwip/sys.h" +#include "lwip/tcpip.h" +#include "lwip/netif.h" +#include "lwip/tcp_impl.h" /* XXX: to access tcp_abandon() */ +#include "lwip/icmp.h" +#include "lwip/icmp6.h" + +/* NetBSD doesn't report POLLHUP for TCP sockets */ +#ifdef __NetBSD__ +# define HAVE_TCP_POLLHUP 0 +#else +# define HAVE_TCP_POLLHUP 1 +#endif + + +/** + * Ring buffer for inbound data. Filled with data from the host + * socket on poll manager thread. Data consumed by scheduling + * tcp_write() to the pcb on the lwip thread. + * + * NB: There is actually third party present, the lwip stack itself. + * Thus the buffer doesn't have dual free vs. data split, but rather + * three-way free / send and unACKed data / unsent data split. + */ +struct ringbuf { + char *buf; + size_t bufsize; + + /* + * Start of free space, producer writes here (up till "unacked"). + */ + volatile size_t vacant; + + /* + * Start of sent but unacknowledged data. The data are "owned" by + * the stack as it may need to retransmit. This is the free space + * limit for producer. + */ + volatile size_t unacked; + + /* + * Start of unsent data, consumer reads/sends from here (up till + * "vacant"). Not declared volatile since it's only accessed from + * the consumer thread. + */ + size_t unsent; +}; + + +/** + */ +struct pxtcp { + /** + * Our poll manager handler. Must be first, strong/weak + * references depend on this "inheritance". + */ + struct pollmgr_handler pmhdl; + + /** + * lwIP (internal/guest) side of the proxied connection. + */ + struct tcp_pcb *pcb; + + /** + * Host (external) side of the proxied connection. + */ + SOCKET sock; + + /** + * Socket events we are currently polling for. + */ + int events; + + /** + * Socket error. Currently used to save connect(2) errors so that + * we can decide if we need to send ICMP error. + */ + int sockerr; + + /** + * Interface that we have got the SYN from. Needed to send ICMP + * with correct source address. + */ + struct netif *netif; + + /** + * For tentatively accepted connections for which we are in + * process of connecting to the real destination this is the + * initial pbuf that we might need to build ICMP error. + * + * When connection is established this is used to hold outbound + * pbuf chain received by pxtcp_pcb_recv() but not yet completely + * forwarded over the socket. We cannot "return" it to lwIP since + * the head of the chain is already sent and freed. + */ + struct pbuf *unsent; + + /** + * Guest has closed its side. Reported to pxtcp_pcb_recv() only + * once and we might not be able to forward it immediately if we + * have unsent pbuf. + */ + int outbound_close; + + /** + * Outbound half-close has been done on the socket. + */ + int outbound_close_done; + + /** + * External has closed its side. We might not be able to forward + * it immediately if we have unforwarded data. + */ + int inbound_close; + + /** + * Inbound half-close has been done on the pcb. + */ + int inbound_close_done; + + /** + * On systems that report POLLHUP as soon as the final FIN is + * received on a socket we cannot continue polling for the rest of + * input, so we have to read (pull) last data from the socket on + * the lwIP thread instead of polling/pushing it from the poll + * manager thread. See comment in pxtcp_pmgr_pump() POLLHUP case. + */ + int inbound_pull; + + + /** + * When poll manager schedules delete we may not be able to delete + * a pxtcp immediately if not all inbound data has been acked by + * the guest: lwIP may need to resend and the data are in pxtcp's + * inbuf::buf. We defer delete until all data are acked to + * pxtcp_pcb_sent(). + * + * It's also implied by inbound_pull. It probably means that + * "deferred" is not a very fortunate name. + */ + int deferred_delete; + + /** + * Ring-buffer for inbound data. + */ + struct ringbuf inbuf; + + /** + * lwIP thread's strong reference to us. + */ + struct pollmgr_refptr *rp; + + + /* + * We use static messages to call functions on the lwIP thread to + * void malloc/free overhead. + */ + struct tcpip_msg msg_delete; /* delete pxtcp */ + struct tcpip_msg msg_reset; /* reset connection and delete pxtcp */ + struct tcpip_msg msg_accept; /* confirm accept of proxied connection */ + struct tcpip_msg msg_outbound; /* trigger send of outbound data */ + struct tcpip_msg msg_inbound; /* trigger send of inbound data */ + struct tcpip_msg msg_inpull; /* trigger pull of last inbound data */ +}; + + + +static struct pxtcp *pxtcp_allocate(void); +static void pxtcp_free(struct pxtcp *); + +static void pxtcp_pcb_associate(struct pxtcp *, struct tcp_pcb *); +static void pxtcp_pcb_dissociate(struct pxtcp *); + +/* poll manager callbacks for pxtcp related channels */ +static int pxtcp_pmgr_chan_add(struct pollmgr_handler *, SOCKET, int); +static int pxtcp_pmgr_chan_pollout(struct pollmgr_handler *, SOCKET, int); +static int pxtcp_pmgr_chan_pollin(struct pollmgr_handler *, SOCKET, int); +#if !HAVE_TCP_POLLHUP +static int pxtcp_pmgr_chan_del(struct pollmgr_handler *, SOCKET, int); +#endif +static int pxtcp_pmgr_chan_reset(struct pollmgr_handler *, SOCKET, int); + +/* helper functions for sending/receiving pxtcp over poll manager channels */ +static ssize_t pxtcp_chan_send(enum pollmgr_slot_t, struct pxtcp *); +static ssize_t pxtcp_chan_send_weak(enum pollmgr_slot_t, struct pxtcp *); +static struct pxtcp *pxtcp_chan_recv(struct pollmgr_handler *, SOCKET, int); +static struct pxtcp *pxtcp_chan_recv_strong(struct pollmgr_handler *, SOCKET, int); + +/* poll manager callbacks for individual sockets */ +static int pxtcp_pmgr_connect(struct pollmgr_handler *, SOCKET, int); +static int pxtcp_pmgr_pump(struct pollmgr_handler *, SOCKET, int); + +static ssize_t pxtcp_sock_read(struct pxtcp *, int *); + +/* convenience functions for poll manager callbacks */ +static int pxtcp_schedule_delete(struct pxtcp *); +static int pxtcp_schedule_reset(struct pxtcp *); +static int pxtcp_schedule_reject(struct pxtcp *); + +/* lwip thread callbacks called via proxy_lwip_post() */ +static void pxtcp_pcb_delete_pxtcp(void *); +static void pxtcp_pcb_reset_pxtcp(void *); +static void pxtcp_pcb_accept_refuse(void *); +static void pxtcp_pcb_accept_confirm(void *); +static void pxtcp_pcb_write_outbound(void *); +static void pxtcp_pcb_write_inbound(void *); +static void pxtcp_pcb_pull_inbound(void *); + +/* tcp pcb callbacks */ +static err_t pxtcp_pcb_heard(void *, struct tcp_pcb *, err_t); /* global */ +static err_t pxtcp_pcb_accept(void *, struct tcp_pcb *, err_t); +static err_t pxtcp_pcb_connected(void *, struct tcp_pcb *, err_t); +static err_t pxtcp_pcb_recv(void *, struct tcp_pcb *, struct pbuf *, err_t); +static err_t pxtcp_pcb_sent(void *, struct tcp_pcb *, u16_t); +static err_t pxtcp_pcb_poll(void *, struct tcp_pcb *); +static void pxtcp_pcb_err(void *, err_t); + +static err_t pxtcp_pcb_forward_outbound(struct pxtcp *, struct pbuf *); +static void pxtcp_pcb_forward_outbound_close(struct pxtcp *); + +static void pxtcp_pcb_forward_inbound(struct pxtcp *); +static void pxtcp_pcb_forward_inbound_close(struct pxtcp *); +DECLINLINE(int) pxtcp_pcb_forward_inbound_done(const struct pxtcp *); +static void pxtcp_pcb_schedule_poll(struct pxtcp *); +static void pxtcp_pcb_cancel_poll(struct pxtcp *); + +static void pxtcp_pcb_reject(struct netif *, struct tcp_pcb *, struct pbuf *, int); +DECLINLINE(void) pxtcp_pcb_maybe_deferred_delete(struct pxtcp *); + +/* poll manager handlers for pxtcp channels */ +static struct pollmgr_handler pxtcp_pmgr_chan_add_hdl; +static struct pollmgr_handler pxtcp_pmgr_chan_pollout_hdl; +static struct pollmgr_handler pxtcp_pmgr_chan_pollin_hdl; +#if !HAVE_TCP_POLLHUP +static struct pollmgr_handler pxtcp_pmgr_chan_del_hdl; +#endif +static struct pollmgr_handler pxtcp_pmgr_chan_reset_hdl; + + +/** + * Init PXTCP - must be run when neither lwIP tcpip thread, nor poll + * manager threads haven't been created yet. + */ +void +pxtcp_init(void) +{ + /* + * Create channels. + */ +#define CHANNEL(SLOT, NAME) do { \ + NAME##_hdl.callback = NAME; \ + NAME##_hdl.data = NULL; \ + NAME##_hdl.slot = -1; \ + pollmgr_add_chan(SLOT, &NAME##_hdl); \ + } while (0) + + CHANNEL(POLLMGR_CHAN_PXTCP_ADD, pxtcp_pmgr_chan_add); + CHANNEL(POLLMGR_CHAN_PXTCP_POLLIN, pxtcp_pmgr_chan_pollin); + CHANNEL(POLLMGR_CHAN_PXTCP_POLLOUT, pxtcp_pmgr_chan_pollout); +#if !HAVE_TCP_POLLHUP + CHANNEL(POLLMGR_CHAN_PXTCP_DEL, pxtcp_pmgr_chan_del); +#endif + CHANNEL(POLLMGR_CHAN_PXTCP_RESET, pxtcp_pmgr_chan_reset); + +#undef CHANNEL + + /* + * Listen to outgoing connection from guest(s). + */ + tcp_proxy_accept(pxtcp_pcb_heard); +} + + +/** + * Syntactic sugar for sending pxtcp pointer over poll manager + * channel. Used by lwip thread functions. + */ +static ssize_t +pxtcp_chan_send(enum pollmgr_slot_t slot, struct pxtcp *pxtcp) +{ + return pollmgr_chan_send(slot, &pxtcp, sizeof(pxtcp)); +} + + +/** + * Syntactic sugar for sending weak reference to pxtcp over poll + * manager channel. Used by lwip thread functions. + */ +static ssize_t +pxtcp_chan_send_weak(enum pollmgr_slot_t slot, struct pxtcp *pxtcp) +{ + pollmgr_refptr_weak_ref(pxtcp->rp); + return pollmgr_chan_send(slot, &pxtcp->rp, sizeof(pxtcp->rp)); +} + + +/** + * Counterpart of pxtcp_chan_send(). + */ +static struct pxtcp * +pxtcp_chan_recv(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + + pxtcp = (struct pxtcp *)pollmgr_chan_recv_ptr(handler, fd, revents); + return pxtcp; +} + + +/** + * Counterpart of pxtcp_chan_send_weak(). + */ +static struct pxtcp * +pxtcp_chan_recv_strong(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pollmgr_refptr *rp; + struct pollmgr_handler *base; + struct pxtcp *pxtcp; + + rp = (struct pollmgr_refptr *)pollmgr_chan_recv_ptr(handler, fd, revents); + base = (struct pollmgr_handler *)pollmgr_refptr_get(rp); + pxtcp = (struct pxtcp *)base; + + return pxtcp; +} + + +/** + * Register pxtcp with poll manager. + * + * Used for POLLMGR_CHAN_PXTCP_ADD and by port-forwarding. Since + * error handling is different in these two cases, we leave it up to + * the caller. + */ +int +pxtcp_pmgr_add(struct pxtcp *pxtcp) +{ + int status; + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->sock >= 0); + LWIP_ASSERT1(pxtcp->pmhdl.callback != NULL); + LWIP_ASSERT1(pxtcp->pmhdl.data == (void *)pxtcp); + LWIP_ASSERT1(pxtcp->pmhdl.slot < 0); + + status = pollmgr_add(&pxtcp->pmhdl, pxtcp->sock, pxtcp->events); + return status; +} + + +/** + * Unregister pxtcp with poll manager. + * + * Used for POLLMGR_CHAN_PXTCP_RESET and by port-forwarding (on error + * leg). + */ +void +pxtcp_pmgr_del(struct pxtcp *pxtcp) +{ + LWIP_ASSERT1(pxtcp != NULL); + + pollmgr_del_slot(pxtcp->pmhdl.slot); +} + + +/** + * POLLMGR_CHAN_PXTCP_ADD handler. + * + * Get new pxtcp from lwip thread and start polling its socket. + */ +static int +pxtcp_pmgr_chan_add(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + int status; + + pxtcp = pxtcp_chan_recv(handler, fd, revents); + DPRINTF0(("pxtcp_add: new pxtcp %p; pcb %p; sock %d\n", + (void *)pxtcp, (void *)pxtcp->pcb, pxtcp->sock)); + + status = pxtcp_pmgr_add(pxtcp); + if (status < 0) { + (void) pxtcp_schedule_reset(pxtcp); + } + + return POLLIN; +} + + +/** + * POLLMGR_CHAN_PXTCP_POLLOUT handler. + * + * pxtcp_pcb_forward_outbound() on the lwIP thread tried to send data + * and failed, it now requests us to poll the socket for POLLOUT and + * schedule pxtcp_pcb_forward_outbound() when sock is writable again. + */ +static int +pxtcp_pmgr_chan_pollout(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + + pxtcp = pxtcp_chan_recv_strong(handler, fd, revents); + DPRINTF0(("pxtcp_pollout: pxtcp %p\n", (void *)pxtcp)); + + if (pxtcp == NULL) { + return POLLIN; + } + + LWIP_ASSERT1(pxtcp->pmhdl.data == (void *)pxtcp); + LWIP_ASSERT1(pxtcp->pmhdl.slot > 0); + + pxtcp->events |= POLLOUT; + pollmgr_update_events(pxtcp->pmhdl.slot, pxtcp->events); + + return POLLIN; +} + + +/** + * POLLMGR_CHAN_PXTCP_POLLIN handler. + */ +static int +pxtcp_pmgr_chan_pollin(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + + pxtcp = pxtcp_chan_recv_strong(handler, fd, revents); + DPRINTF2(("pxtcp_pollin: pxtcp %p\n", (void *)pxtcp)); + + if (pxtcp == NULL) { + return POLLIN; + } + + LWIP_ASSERT1(pxtcp->pmhdl.data == (void *)pxtcp); + LWIP_ASSERT1(pxtcp->pmhdl.slot > 0); + + if (pxtcp->inbound_close) { + return POLLIN; + } + + pxtcp->events |= POLLIN; + pollmgr_update_events(pxtcp->pmhdl.slot, pxtcp->events); + + return POLLIN; +} + + +#if !HAVE_TCP_POLLHUP +/** + * POLLMGR_CHAN_PXTCP_DEL handler. + * + * Schedule pxtcp deletion. We only need this if host system doesn't + * report POLLHUP for fully closed tcp sockets. + */ +static int +pxtcp_pmgr_chan_del(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + + pxtcp = pxtcp_chan_recv_strong(handler, fd, revents); + if (pxtcp == NULL) { + return POLLIN; + } + + DPRINTF(("PXTCP_DEL: pxtcp %p; pcb %p; sock %d\n", + (void *)pxtcp, (void *)pxtcp->pcb, pxtcp->sock)); + + LWIP_ASSERT1(pxtcp->pmhdl.callback != NULL); + LWIP_ASSERT1(pxtcp->pmhdl.data == (void *)pxtcp); + + LWIP_ASSERT1(pxtcp->inbound_close); /* EOF read */ + LWIP_ASSERT1(pxtcp->outbound_close_done); /* EOF sent */ + + pxtcp_pmgr_del(pxtcp); + (void) pxtcp_schedule_delete(pxtcp); + + return POLLIN; +} +#endif /* !HAVE_TCP_POLLHUP */ + + +/** + * POLLMGR_CHAN_PXTCP_RESET handler. + * + * Close the socket with RST and delete pxtcp. + */ +static int +pxtcp_pmgr_chan_reset(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + + pxtcp = pxtcp_chan_recv_strong(handler, fd, revents); + if (pxtcp == NULL) { + return POLLIN; + } + + DPRINTF0(("PXTCP_RESET: pxtcp %p; pcb %p; sock %d\n", + (void *)pxtcp, (void *)pxtcp->pcb, pxtcp->sock)); + + LWIP_ASSERT1(pxtcp->pmhdl.callback != NULL); + LWIP_ASSERT1(pxtcp->pmhdl.data == (void *)pxtcp); + + pxtcp_pmgr_del(pxtcp); + + proxy_reset_socket(pxtcp->sock); + pxtcp->sock = INVALID_SOCKET; + + (void) pxtcp_schedule_reset(pxtcp); + + return POLLIN; +} + + +static struct pxtcp * +pxtcp_allocate(void) +{ + struct pxtcp *pxtcp; + + pxtcp = (struct pxtcp *)malloc(sizeof(*pxtcp)); + if (pxtcp == NULL) { + return NULL; + } + + pxtcp->pmhdl.callback = NULL; + pxtcp->pmhdl.data = (void *)pxtcp; + pxtcp->pmhdl.slot = -1; + + pxtcp->pcb = NULL; + pxtcp->sock = INVALID_SOCKET; + pxtcp->events = 0; + pxtcp->sockerr = 0; + pxtcp->netif = NULL; + pxtcp->unsent = NULL; + pxtcp->outbound_close = 0; + pxtcp->outbound_close_done = 0; + pxtcp->inbound_close = 0; + pxtcp->inbound_close_done = 0; + pxtcp->inbound_pull = 0; + pxtcp->deferred_delete = 0; + + pxtcp->inbuf.bufsize = 64 * 1024; + pxtcp->inbuf.buf = (char *)malloc(pxtcp->inbuf.bufsize); + if (pxtcp->inbuf.buf == NULL) { + free(pxtcp); + return NULL; + } + pxtcp->inbuf.vacant = 0; + pxtcp->inbuf.unacked = 0; + pxtcp->inbuf.unsent = 0; + + pxtcp->rp = pollmgr_refptr_create(&pxtcp->pmhdl); + if (pxtcp->rp == NULL) { + free(pxtcp->inbuf.buf); + free(pxtcp); + return NULL; + } + +#define CALLBACK_MSG(MSG, FUNC) \ + do { \ + pxtcp->MSG.type = TCPIP_MSG_CALLBACK_STATIC; \ + pxtcp->MSG.sem = NULL; \ + pxtcp->MSG.msg.cb.function = FUNC; \ + pxtcp->MSG.msg.cb.ctx = (void *)pxtcp; \ + } while (0) + + CALLBACK_MSG(msg_delete, pxtcp_pcb_delete_pxtcp); + CALLBACK_MSG(msg_reset, pxtcp_pcb_reset_pxtcp); + CALLBACK_MSG(msg_accept, pxtcp_pcb_accept_confirm); + CALLBACK_MSG(msg_outbound, pxtcp_pcb_write_outbound); + CALLBACK_MSG(msg_inbound, pxtcp_pcb_write_inbound); + CALLBACK_MSG(msg_inpull, pxtcp_pcb_pull_inbound); + +#undef CALLBACK_MSG + + return pxtcp; +} + + +/** + * Exported to fwtcp to create pxtcp for incoming port-forwarded + * connections. Completed with pcb in pxtcp_pcb_connect(). + */ +struct pxtcp * +pxtcp_create_forwarded(SOCKET sock) +{ + struct pxtcp *pxtcp; + + pxtcp = pxtcp_allocate(); + if (pxtcp == NULL) { + return NULL; + } + + pxtcp->sock = sock; + pxtcp->pmhdl.callback = pxtcp_pmgr_pump; + pxtcp->events = 0; + + return pxtcp; +} + + +static void +pxtcp_pcb_associate(struct pxtcp *pxtcp, struct tcp_pcb *pcb) +{ + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pcb != NULL); + + pxtcp->pcb = pcb; + + tcp_arg(pcb, pxtcp); + + tcp_recv(pcb, pxtcp_pcb_recv); + tcp_sent(pcb, pxtcp_pcb_sent); + tcp_poll(pcb, NULL, 255); + tcp_err(pcb, pxtcp_pcb_err); +} + + +static void +pxtcp_free(struct pxtcp *pxtcp) +{ + if (pxtcp->unsent != NULL) { + pbuf_free(pxtcp->unsent); + } + if (pxtcp->inbuf.buf != NULL) { + free(pxtcp->inbuf.buf); + } + free(pxtcp); +} + + +/** + * Counterpart to pxtcp_create_forwarded() to destruct pxtcp that + * fwtcp failed to register with poll manager to post to lwip thread + * for doing connect. + */ +void +pxtcp_cancel_forwarded(struct pxtcp *pxtcp) +{ + LWIP_ASSERT1(pxtcp->pcb == NULL); + pxtcp_pcb_reset_pxtcp(pxtcp); +} + + +static void +pxtcp_pcb_dissociate(struct pxtcp *pxtcp) +{ + if (pxtcp == NULL || pxtcp->pcb == NULL) { + return; + } + + DPRINTF(("%s: pxtcp %p <-> pcb %p\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb)); + + /* + * We must have dissociated from a fully closed pcb immediately + * since lwip recycles them and we don't wan't to mess with what + * would be someone else's pcb that we happen to have a stale + * pointer to. + */ + LWIP_ASSERT1(pxtcp->pcb->callback_arg == pxtcp); + + tcp_recv(pxtcp->pcb, NULL); + tcp_sent(pxtcp->pcb, NULL); + tcp_poll(pxtcp->pcb, NULL, 255); + tcp_err(pxtcp->pcb, NULL); + tcp_arg(pxtcp->pcb, NULL); + pxtcp->pcb = NULL; +} + + +/** + * Lwip thread callback invoked via pxtcp::msg_delete + * + * Since we use static messages to communicate to the lwip thread, we + * cannot delete pxtcp without making sure there are no unprocessed + * messages in the lwip thread mailbox. + * + * The easiest way to ensure that is to send this "delete" message as + * the last one and when it's processed we know there are no more and + * it's safe to delete pxtcp. + * + * Poll manager handlers should use pxtcp_schedule_delete() + * convenience function. + */ +static void +pxtcp_pcb_delete_pxtcp(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + + DPRINTF(("%s: pxtcp %p, pcb %p, sock %d%s\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb, pxtcp->sock, + (pxtcp->deferred_delete && !pxtcp->inbound_pull + ? " (was deferred)" : ""))); + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->pmhdl.slot < 0); + LWIP_ASSERT1(pxtcp->outbound_close_done); + LWIP_ASSERT1(pxtcp->inbound_close); /* not necessarily done */ + + + /* + * pxtcp is no longer registered with poll manager, so it's safe + * to close the socket. + */ + if (pxtcp->sock != INVALID_SOCKET) { + closesocket(pxtcp->sock); + pxtcp->sock = INVALID_SOCKET; + } + + /* + * We might have already dissociated from a fully closed pcb, or + * guest might have sent us a reset while msg_delete was in + * transit. If there's no pcb, we are done. + */ + if (pxtcp->pcb == NULL) { + pollmgr_refptr_unref(pxtcp->rp); + pxtcp_free(pxtcp); + return; + } + + /* + * Have we completely forwarded all inbound traffic to the guest? + * + * We may still be waiting for ACKs. We may have failed to send + * some of the data (tcp_write() failed with ERR_MEM). We may + * have failed to send the FIN (tcp_shutdown() failed with + * ERR_MEM). + */ + if (pxtcp_pcb_forward_inbound_done(pxtcp)) { + pxtcp_pcb_dissociate(pxtcp); + pollmgr_refptr_unref(pxtcp->rp); + pxtcp_free(pxtcp); + } + else { + DPRINTF2(("delete: pxtcp %p; pcb %p:" + " unacked %d, unsent %d, vacant %d, %s - DEFER!\n", + (void *)pxtcp, (void *)pxtcp->pcb, + (int)pxtcp->inbuf.unacked, + (int)pxtcp->inbuf.unsent, + (int)pxtcp->inbuf.vacant, + pxtcp->inbound_close_done ? "FIN sent" : "FIN is NOT sent")); + + LWIP_ASSERT1(!pxtcp->deferred_delete); + pxtcp->deferred_delete = 1; + } +} + + +/** + * If we couldn't delete pxtcp right away in the msg_delete callback + * from the poll manager thread, we repeat the check at the end of + * relevant pcb callbacks. + */ +DECLINLINE(void) +pxtcp_pcb_maybe_deferred_delete(struct pxtcp *pxtcp) +{ + if (pxtcp->deferred_delete && pxtcp_pcb_forward_inbound_done(pxtcp)) { + pxtcp_pcb_delete_pxtcp(pxtcp); + } +} + + +/** + * Poll manager callbacks should use this convenience wrapper to + * schedule pxtcp deletion on the lwip thread and to deregister from + * the poll manager. + */ +static int +pxtcp_schedule_delete(struct pxtcp *pxtcp) +{ + /* + * If pollmgr_refptr_get() is called by any channel before + * scheduled deletion happens, let them know we are gone. + */ + pxtcp->pmhdl.slot = -1; + + /* + * Schedule deletion. Since poll manager thread may be pre-empted + * right after we send the message, the deletion may actually + * happen on the lwip thread before we return from this function, + * so it's not safe to refer to pxtcp after this call. + */ + proxy_lwip_post(&pxtcp->msg_delete); + + /* tell poll manager to deregister us */ + return -1; +} + + +/** + * Lwip thread callback invoked via pxtcp::msg_reset + * + * Like pxtcp_pcb_delete(), but sends RST to the guest before + * deleting this pxtcp. + */ +static void +pxtcp_pcb_reset_pxtcp(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + LWIP_ASSERT1(pxtcp != NULL); + + DPRINTF0(("%s: pxtcp %p, pcb %p, sock %d\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb, pxtcp->sock)); + + if (pxtcp->sock != INVALID_SOCKET) { + proxy_reset_socket(pxtcp->sock); + pxtcp->sock = INVALID_SOCKET; + } + + if (pxtcp->pcb != NULL) { + struct tcp_pcb *pcb = pxtcp->pcb; + pxtcp_pcb_dissociate(pxtcp); + tcp_abort(pcb); + } + + pollmgr_refptr_unref(pxtcp->rp); + pxtcp_free(pxtcp); +} + + + +/** + * Poll manager callbacks should use this convenience wrapper to + * schedule pxtcp reset and deletion on the lwip thread and to + * deregister from the poll manager. + * + * See pxtcp_schedule_delete() for additional comments. + */ +static int +pxtcp_schedule_reset(struct pxtcp *pxtcp) +{ + pxtcp->pmhdl.slot = -1; + proxy_lwip_post(&pxtcp->msg_reset); + return -1; +} + + +/** + * Reject proxy connection attempt. Depending on the cause (sockerr) + * we may just drop the pcb silently, generate an ICMP datagram or + * send TCP reset. + */ +static void +pxtcp_pcb_reject(struct netif *netif, struct tcp_pcb *pcb, + struct pbuf *p, int sockerr) +{ + struct netif *oif; + int reset = 0; + + oif = ip_current_netif(); + ip_current_netif() = netif; + + if (sockerr == ECONNREFUSED) { + reset = 1; + } + else if (PCB_ISIPV6(pcb)) { + if (sockerr == EHOSTDOWN) { + icmp6_dest_unreach(p, ICMP6_DUR_ADDRESS); /* XXX: ??? */ + } + else if (sockerr == EHOSTUNREACH + || sockerr == ENETDOWN + || sockerr == ENETUNREACH) + { + icmp6_dest_unreach(p, ICMP6_DUR_NO_ROUTE); + } + } + else { + if (sockerr == EHOSTDOWN + || sockerr == EHOSTUNREACH + || sockerr == ENETDOWN + || sockerr == ENETUNREACH) + { + icmp_dest_unreach(p, ICMP_DUR_HOST); + } + } + + ip_current_netif() = oif; + + tcp_abandon(pcb, reset); +} + + +/** + * Called from poll manager thread via pxtcp::msg_accept when proxy + * failed to connect to the destination. Also called when we failed + * to register pxtcp with poll manager. + * + * This is like pxtcp_pcb_reset_pxtcp() but is more discriminate in + * how this unestablished connection is terminated. + */ +static void +pxtcp_pcb_accept_refuse(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + + DPRINTF0(("%s: pxtcp %p, pcb %p, sock %d: errno %d\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb, + pxtcp->sock, pxtcp->sockerr)); + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->sock == INVALID_SOCKET); + + if (pxtcp->pcb != NULL) { + struct tcp_pcb *pcb = pxtcp->pcb; + pxtcp_pcb_dissociate(pxtcp); + pxtcp_pcb_reject(pxtcp->netif, pcb, pxtcp->unsent, pxtcp->sockerr); + } + + pollmgr_refptr_unref(pxtcp->rp); + pxtcp_free(pxtcp); +} + + +/** + * Convenience wrapper for poll manager connect callback to reject + * connection attempt. + * + * Like pxtcp_schedule_reset(), but the callback is more discriminate + * in how this unestablished connection is terminated. + */ +static int +pxtcp_schedule_reject(struct pxtcp *pxtcp) +{ + pxtcp->msg_accept.msg.cb.function = pxtcp_pcb_accept_refuse; + pxtcp->pmhdl.slot = -1; + proxy_lwip_post(&pxtcp->msg_accept); + return -1; +} + + +/** + * Global tcp_proxy_accept() callback for proxied outgoing TCP + * connections from guest(s). + */ +static err_t +pxtcp_pcb_heard(void *arg, struct tcp_pcb *newpcb, err_t error) +{ + struct pbuf *p = (struct pbuf *)arg; + struct pxtcp *pxtcp; + ipX_addr_t dst_addr; + int sdom; + SOCKET sock; + ssize_t nsent; + int sockerr = 0; + + LWIP_UNUSED_ARG(error); /* always ERR_OK */ + + /* + * TCP first calls accept callback when it receives the first SYN + * and "tentatively accepts" new proxied connection attempt. When + * proxy "confirms" the SYN and sends SYN|ACK and the guest + * replies with ACK the accept callback is called again, this time + * with the established connection. + */ + LWIP_ASSERT1(newpcb->state == SYN_RCVD_0); + tcp_accept(newpcb, pxtcp_pcb_accept); + tcp_arg(newpcb, NULL); + + tcp_setprio(newpcb, TCP_PRIO_MAX); + + pxremap_outbound_ipX(PCB_ISIPV6(newpcb), &dst_addr, &newpcb->local_ip); + + sdom = PCB_ISIPV6(newpcb) ? PF_INET6 : PF_INET; + sock = proxy_connected_socket(sdom, SOCK_STREAM, + &dst_addr, newpcb->local_port); + if (sock == INVALID_SOCKET) { + sockerr = errno; + goto abort; + } + + pxtcp = pxtcp_allocate(); + if (pxtcp == NULL) { + proxy_reset_socket(sock); + goto abort; + } + + /* save initial datagram in case we need to reply with ICMP */ + pbuf_ref(p); + pxtcp->unsent = p; + pxtcp->netif = ip_current_netif(); + + pxtcp_pcb_associate(pxtcp, newpcb); + pxtcp->sock = sock; + + pxtcp->pmhdl.callback = pxtcp_pmgr_connect; + pxtcp->events = POLLOUT; + + nsent = pxtcp_chan_send(POLLMGR_CHAN_PXTCP_ADD, pxtcp); + if (nsent < 0) { + pxtcp->sock = INVALID_SOCKET; + proxy_reset_socket(sock); + pxtcp_pcb_accept_refuse(pxtcp); + return ERR_ABRT; + } + + return ERR_OK; + + abort: + DPRINTF0(("%s: pcb %p, sock %d: errno %d\n", + __func__, (void *)newpcb, sock, sockerr)); + pxtcp_pcb_reject(ip_current_netif(), newpcb, p, sockerr); + return ERR_ABRT; +} + + +/** + * tcp_proxy_accept() callback for accepted proxied outgoing TCP + * connections from guest(s). This is "real" accept with three-way + * handshake completed. + */ +static err_t +pxtcp_pcb_accept(void *arg, struct tcp_pcb *pcb, err_t error) +{ + struct pxtcp *pxtcp = (struct pxtcp *)arg; + + LWIP_UNUSED_ARG(pcb); /* used only in asserts */ + LWIP_UNUSED_ARG(error); /* always ERR_OK */ + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->pcb = pcb); + LWIP_ASSERT1(pcb->callback_arg == pxtcp); + + /* send any inbound data that are already queued */ + pxtcp_pcb_forward_inbound(pxtcp); + return ERR_OK; +} + + +/** + * Initial poll manager callback for proxied outgoing TCP connections. + * pxtcp_pcb_accept() sets pxtcp::pmhdl::callback to this. + * + * Waits for connect(2) to the destination to complete. On success + * replaces itself with pxtcp_pmgr_pump() callback common to all + * established TCP connections. + */ +static int +pxtcp_pmgr_connect(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + int sockerr; + + pxtcp = (struct pxtcp *)handler->data; + LWIP_ASSERT1(handler == &pxtcp->pmhdl); + LWIP_ASSERT1(fd == pxtcp->sock); + + if (revents & (POLLNVAL | POLLHUP | POLLERR)) { + if (revents & POLLNVAL) { + pxtcp->sock = INVALID_SOCKET; + pxtcp->sockerr = ETIMEDOUT; + } + else { + socklen_t optlen = (socklen_t)sizeof(sockerr); + int status; + SOCKET s; + + status = getsockopt(pxtcp->sock, SOL_SOCKET, SO_ERROR, + (char *)&pxtcp->sockerr, &optlen); + if (status < 0) { /* should not happen */ + sockerr = errno; /* ??? */ + perror("connect: getsockopt"); + } + else { +#ifndef RT_OS_WINDOWS + errno = pxtcp->sockerr; /* to avoid strerror_r */ +#else + /* see winutils.h */ + WSASetLastError(pxtcp->sockerr); +#endif + perror("connect"); + } + s = pxtcp->sock; + pxtcp->sock = INVALID_SOCKET; + closesocket(s); + } + return pxtcp_schedule_reject(pxtcp); + } + + if (revents & POLLOUT) { /* connect is successful */ + /* confirm accept to the guest */ + proxy_lwip_post(&pxtcp->msg_accept); + + /* + * Switch to common callback used for all established proxied + * connections. + */ + pxtcp->pmhdl.callback = pxtcp_pmgr_pump; + + /* + * Initially we poll for incoming traffic only. Outgoing + * traffic is fast-forwarded by pxtcp_pcb_recv(); if it fails + * it will ask us to poll for POLLOUT too. + */ + pxtcp->events = POLLIN; + return pxtcp->events; + } + + /* should never get here */ + DPRINTF0(("%s: pxtcp %p, sock %d: unexpected revents 0x%x\n", + __func__, (void *)pxtcp, fd, revents)); + return pxtcp_schedule_reset(pxtcp); +} + + +/** + * Called from poll manager thread via pxtcp::msg_accept when proxy + * connected to the destination. Finalize accept by sending SYN|ACK + * to the guest. + */ +static void +pxtcp_pcb_accept_confirm(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + err_t error; + + LWIP_ASSERT1(pxtcp != NULL); + if (pxtcp->pcb == NULL) { + return; + } + + /* we are not going to reply with ICMP, so we can drop initial pbuf */ + LWIP_ASSERT1(pxtcp->unsent != NULL); + pbuf_free(pxtcp->unsent); + pxtcp->unsent = NULL; + + error = tcp_proxy_accept_confirm(pxtcp->pcb); + + /* + * If lwIP failed to enqueue SYN|ACK because it's out of pbufs it + * abandons the pcb. Retrying that is not very easy, since it + * would require keeping "fractional state". From guest's point + * of view there is no reply to its SYN so it will either resend + * the SYN (effetively triggering full connection retry for us), + * or it will eventually time out. + */ + if (error == ERR_ABRT) { + pxtcp->pcb = NULL; /* pcb is gone */ + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_RESET, pxtcp); + } + + /* + * else if (error != ERR_OK): even if tcp_output() failed with + * ERR_MEM - don't give up, that SYN|ACK is enqueued and will be + * retransmitted eventually. + */ +} + + +/** + * Entry point for port-forwarding. + * + * fwtcp accepts new incoming connection, creates pxtcp for the socket + * (with no pcb yet) and adds it to the poll manager (polling for + * errors only). Then it calls this function to construct the pcb and + * perform connection to the guest. + */ +void +pxtcp_pcb_connect(struct pxtcp *pxtcp, const struct fwspec *fwspec) +{ + struct sockaddr_storage ss; + socklen_t sslen; + struct tcp_pcb *pcb; + ipX_addr_t src_addr, dst_addr; + u16_t src_port, dst_port; + int status; + err_t error; + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->pcb == NULL); + LWIP_ASSERT1(fwspec->stype == SOCK_STREAM); + + pcb = tcp_new(); + if (pcb == NULL) { + goto reset; + } + + tcp_setprio(pcb, TCP_PRIO_MAX); + pxtcp_pcb_associate(pxtcp, pcb); + + sslen = sizeof(ss); + status = getpeername(pxtcp->sock, (struct sockaddr *)&ss, &sslen); + if (status == SOCKET_ERROR) { + goto reset; + } + + /* nit: comapres PF and AF, but they are the same everywhere */ + LWIP_ASSERT1(ss.ss_family == fwspec->sdom); + + status = fwany_ipX_addr_set_src(&src_addr, (const struct sockaddr *)&ss); + if (status == PXREMAP_FAILED) { + goto reset; + } + + if (ss.ss_family == PF_INET) { + const struct sockaddr_in *peer4 = (const struct sockaddr_in *)&ss; + + src_port = peer4->sin_port; + + memcpy(&dst_addr.ip4, &fwspec->dst.sin.sin_addr, sizeof(ip_addr_t)); + dst_port = fwspec->dst.sin.sin_port; + } + else { /* PF_INET6 */ + const struct sockaddr_in6 *peer6 = (const struct sockaddr_in6 *)&ss; + ip_set_v6(pcb, 1); + + src_port = peer6->sin6_port; + + memcpy(&dst_addr.ip6, &fwspec->dst.sin6.sin6_addr, sizeof(ip6_addr_t)); + dst_port = fwspec->dst.sin6.sin6_port; + } + + /* lwip port arguments are in host order */ + src_port = ntohs(src_port); + dst_port = ntohs(dst_port); + + error = tcp_proxy_bind(pcb, ipX_2_ip(&src_addr), src_port); + if (error != ERR_OK) { + goto reset; + } + + error = tcp_connect(pcb, ipX_2_ip(&dst_addr), dst_port, + /* callback: */ pxtcp_pcb_connected); + if (error != ERR_OK) { + goto reset; + } + + return; + + reset: + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_RESET, pxtcp); +} + + +/** + * Port-forwarded connection to guest is successful, pump data. + */ +static err_t +pxtcp_pcb_connected(void *arg, struct tcp_pcb *pcb, err_t error) +{ + struct pxtcp *pxtcp = (struct pxtcp *)arg; + + LWIP_ASSERT1(error == ERR_OK); /* always called with ERR_OK */ + LWIP_UNUSED_ARG(error); + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->pcb == pcb); + LWIP_ASSERT1(pcb->callback_arg == pxtcp); + LWIP_UNUSED_ARG(pcb); + + DPRINTF0(("%s: new pxtcp %p; pcb %p; sock %d\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb, pxtcp->sock)); + + /* ACK on connection is like ACK on data in pxtcp_pcb_sent() */ + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_POLLIN, pxtcp); + + return ERR_OK; +} + + +/** + * tcp_recv() callback. + */ +static err_t +pxtcp_pcb_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t error) +{ + struct pxtcp *pxtcp = (struct pxtcp *)arg; + + LWIP_ASSERT1(error == ERR_OK); /* always called with ERR_OK */ + LWIP_UNUSED_ARG(error); + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->pcb == pcb); + LWIP_ASSERT1(pcb->callback_arg == pxtcp); + LWIP_UNUSED_ARG(pcb); + + + /* + * Have we done sending previous batch? + */ + if (pxtcp->unsent != NULL) { + if (p != NULL) { + /* + * Return an error to tell TCP to hold onto that pbuf. + * It will be presented to us later from tcp_fasttmr(). + */ + return ERR_WOULDBLOCK; + } + else { + /* + * Unlike data, p == NULL indicating orderly shutdown is + * NOT presented to us again + */ + pxtcp->outbound_close = 1; + return ERR_OK; + } + } + + + /* + * Guest closed? + */ + if (p == NULL) { + pxtcp->outbound_close = 1; + pxtcp_pcb_forward_outbound_close(pxtcp); + return ERR_OK; + } + + + /* + * Got data, send what we can without blocking. + */ + return pxtcp_pcb_forward_outbound(pxtcp, p); +} + + +/** + * Guest half-closed its TX side of the connection. + * + * Called either immediately from pxtcp_pcb_recv() when it gets NULL, + * or from pxtcp_pcb_forward_outbound() when it finishes forwarding + * previously unsent data and sees pxtcp::outbound_close flag saved by + * pxtcp_pcb_recv(). + */ +static void +pxtcp_pcb_forward_outbound_close(struct pxtcp *pxtcp) +{ + struct tcp_pcb *pcb; + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->outbound_close); + LWIP_ASSERT1(!pxtcp->outbound_close_done); + + pcb = pxtcp->pcb; + LWIP_ASSERT1(pcb != NULL); + + DPRINTF(("outbound_close: pxtcp %p; pcb %p %s\n", + (void *)pxtcp, (void *)pcb, tcp_debug_state_str(pcb->state))); + + + /* + * NB: set the flag first, since shutdown() will trigger POLLHUP + * if inbound is already closed, and poll manager asserts + * outbound_close_done (may be it should not?). + */ + pxtcp->outbound_close_done = 1; + shutdown(pxtcp->sock, SHUT_WR); /* half-close the socket */ + +#if !HAVE_TCP_POLLHUP + /* + * On NetBSD POLLHUP is not reported for TCP sockets, so we need + * to nudge poll manager manually. + */ + if (pxtcp->inbound_close) { + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_DEL, pxtcp); + } +#endif + + + /* no more outbound data coming to us */ + tcp_recv(pcb, NULL); + + /* + * If we have already done inbound close previously (active close + * on the pcb), then we must not hold onto a pcb in TIME_WAIT + * state since those will be recycled by lwip when it runs out of + * free pcbs in the pool. + * + * The test is true also for a pcb in CLOSING state that waits + * just for the ACK of its FIN (to transition to TIME_WAIT). + */ + if (pxtcp_pcb_forward_inbound_done(pxtcp)) { + pxtcp_pcb_dissociate(pxtcp); + } +} + + +/** + * Forward outbound data from pcb to socket. + * + * Called by pxtcp_pcb_recv() to forward new data and by callout + * triggered by POLLOUT on the socket to send previously unsent data. + * + * (Re)scehdules one-time callout if not all data are sent. + */ +static err_t +pxtcp_pcb_forward_outbound(struct pxtcp *pxtcp, struct pbuf *p) +{ + struct pbuf *qs, *q; + size_t qoff; + size_t forwarded; + int sockerr; + +#if defined(MSG_NOSIGNAL) + const int send_flags = MSG_NOSIGNAL; +#else + const int send_flags = 0; +#endif + + + LWIP_ASSERT1(pxtcp->unsent == NULL || pxtcp->unsent == p); + + forwarded = 0; + sockerr = 0; + + q = NULL; + qoff = 0; + + qs = p; + while (qs != NULL) { +#ifndef RT_OS_WINDOWS + struct msghdr mh; +#else + int rc; +#endif + IOVEC iov[8]; + const size_t iovsize = sizeof(iov)/sizeof(iov[0]); + size_t fwd1; + ssize_t nsent; + size_t i; + + fwd1 = 0; + for (i = 0, q = qs; i < iovsize && q != NULL; ++i, q = q->next) { + LWIP_ASSERT1(q->len > 0); + IOVEC_SET_BASE(iov[i], q->payload); + IOVEC_SET_LEN(iov[i], q->len); + fwd1 += q->len; + } + +#ifndef RT_OS_WINDOWS + memset(&mh, 0, sizeof(mh)); + mh.msg_iov = iov; + mh.msg_iovlen = i; + + nsent = sendmsg(pxtcp->sock, &mh, send_flags); +#else + /** + * WSASend(,,,DWORD *,,,) - takes SSIZE_T (64bit value) ... so all nsent's + * bits should be zeroed before passing to WSASent. + */ + nsent = 0; + rc = WSASend(pxtcp->sock, iov, (DWORD)i, (DWORD *)&nsent, 0, NULL, NULL); + if (rc == SOCKET_ERROR) { + /* WSASent reports SOCKET_ERROR and updates error accessible with + * WSAGetLastError(). We assign nsent to -1, enforcing code below + * to access error in BSD style. + */ + warn("pxtcp_pcb_forward_outbound:WSASend error:%d nsent:%d\n", + WSAGetLastError(), + nsent); + nsent = -1; + } +#endif + + if (nsent == (ssize_t)fwd1) { + /* successfully sent this chain fragment completely */ + forwarded += nsent; + qs = q; + } + else if (nsent >= 0) { + /* successfully sent only some data */ + forwarded += nsent; + + /* find the first pbuf that was not completely forwarded */ + qoff = nsent; + for (i = 0, q = qs; i < iovsize && q != NULL; ++i, q = q->next) { + if (qoff < q->len) { + break; + } + qoff -= q->len; + } + LWIP_ASSERT1(q != NULL); + LWIP_ASSERT1(qoff < q->len); + break; + } + else { + /* + * Some errors are really not errors - if we get them, + * it's not different from getting nsent == 0, so filter + * them out here. + */ + if (errno != EWOULDBLOCK + && errno != EAGAIN + && errno != ENOBUFS + && errno != ENOMEM + && errno != EINTR) + { + sockerr = errno; + } + q = qs; + qoff = 0; + break; + } + } + + if (forwarded > 0) { + tcp_recved(pxtcp->pcb, (u16_t)forwarded); + } + + if (q == NULL) { /* everything is forwarded? */ + LWIP_ASSERT1(sockerr == 0); + LWIP_ASSERT1(forwarded == p->tot_len); + + pxtcp->unsent = NULL; + pbuf_free(p); + if (pxtcp->outbound_close) { + pxtcp_pcb_forward_outbound_close(pxtcp); + } + } + else { + if (q != p) { + /* free forwarded pbufs at the beginning of the chain */ + pbuf_ref(q); + pbuf_free(p); + } + if (qoff > 0) { + /* advance payload pointer past the forwarded part */ + pbuf_header(q, -(s16_t)qoff); + } + pxtcp->unsent = q; + + /* + * Have sendmsg() failed? + * + * Connection reset will be detected by poll and + * pxtcp_schedule_reset() will be called. + * + * Otherwise something *really* unexpected must have happened, + * so we'd better abort. + */ + if (sockerr != 0 && sockerr != ECONNRESET) { + struct tcp_pcb *pcb = pxtcp->pcb; + pxtcp_pcb_dissociate(pxtcp); + + tcp_abort(pcb); + + /* call error callback manually since we've already dissociated */ + pxtcp_pcb_err((void *)pxtcp, ERR_ABRT); + return ERR_ABRT; + } + + /* schedule one-shot POLLOUT on the socket */ + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_POLLOUT, pxtcp); + } + return ERR_OK; +} + + +/** + * Callback from poll manager (on POLLOUT) to send data from + * pxtcp::unsent pbuf to socket. + */ +static void +pxtcp_pcb_write_outbound(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + LWIP_ASSERT1(pxtcp != NULL); + + if (pxtcp->pcb == NULL) { + return; + } + + pxtcp_pcb_forward_outbound(pxtcp, pxtcp->unsent); +} + + +/** + * Common poll manager callback used by both outgoing and incoming + * (port-forwarded) connections that has connected socket. + */ +static int +pxtcp_pmgr_pump(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxtcp *pxtcp; + int status; + int sockerr; + + pxtcp = (struct pxtcp *)handler->data; + LWIP_ASSERT1(handler == &pxtcp->pmhdl); + LWIP_ASSERT1(fd == pxtcp->sock); + + if (revents & POLLNVAL) { + pxtcp->sock = INVALID_SOCKET; + return pxtcp_schedule_reset(pxtcp); + } + + if (revents & POLLERR) { + socklen_t optlen = (socklen_t)sizeof(sockerr); + + status = getsockopt(pxtcp->sock, SOL_SOCKET, SO_ERROR, + (char *)&sockerr, &optlen); + if (status < 0) { /* should not happen */ + perror("getsockopt"); + sockerr = ECONNRESET; + } + + DPRINTF0(("sock %d: errno %d\n", fd, sockerr)); + return pxtcp_schedule_reset(pxtcp); + } + + if (revents & POLLOUT) { + pxtcp->events &= ~POLLOUT; + proxy_lwip_post(&pxtcp->msg_outbound); + } + + if (revents & POLLIN) { + ssize_t nread; + int stop_pollin; + + nread = pxtcp_sock_read(pxtcp, &stop_pollin); + if (nread < 0) { + sockerr = -(int)nread; + DPRINTF0(("sock %d: errno %d\n", fd, sockerr)); + return pxtcp_schedule_reset(pxtcp); + } + + if (stop_pollin) { + pxtcp->events &= ~POLLIN; + } + + if (nread > 0) { + proxy_lwip_post(&pxtcp->msg_inbound); +#if !HAVE_TCP_POLLHUP + /* + * If host does not report POLLHUP for closed sockets + * (e.g. NetBSD) we should check for full close manually. + */ + if (pxtcp->inbound_close && pxtcp->outbound_close_done) { + LWIP_ASSERT1((revents & POLLHUP) == 0); + return pxtcp_schedule_delete(pxtcp); + } +#endif + } + } + +#if !HAVE_TCP_POLLHUP + LWIP_ASSERT1((revents & POLLHUP) == 0); +#else + if (revents & POLLHUP) { + /* + * Linux and Darwin seems to report POLLHUP when both + * directions are shut down. And they do report POLLHUP even + * when there's unread data (which they aslo report as POLLIN + * along with that POLLHUP). + * + * FreeBSD (from source inspection) seems to follow Linux, + * reporting POLLHUP when both directions are shut down, but + * POLLHUP is always accompanied with POLLIN. + * + * NetBSD never reports POLLHUP for sockets. + * + * --- + * + * If external half-closes first, we don't get POLLHUP, we + * recv 0 bytes from the socket as EOF indicator, stop polling + * for POLLIN and poll with events == 0 (with occasional + * one-shot POLLOUT). When guest eventually closes, we get + * POLLHUP. + * + * If guest half-closes first things are more tricky. As soon + * as host sees the FIN from external it will spam POLLHUP, + * even when there's unread data. The problem is that we + * might have stopped polling for POLLIN because the ring + * buffer is full or we were polling POLLIN but can't read all + * of the data becuase buffer doesn't have enough space. + * Either way, there's unread data but we can't keep polling + * the socket. + */ + DPRINTF(("sock %d: HUP\n", fd)); + LWIP_ASSERT1(pxtcp->outbound_close_done); + + if (pxtcp->inbound_close) { + /* there's no unread data, we are done */ + return pxtcp_schedule_delete(pxtcp); + } + else { + /* DPRINTF */ { +#ifndef RT_OS_WINDOWS + int unread; +#else + u_long unread; +#endif + status = ioctlsocket(fd, FIONREAD, &unread); + if (status == SOCKET_ERROR) { + perror("FIONREAD"); + } + else { + DPRINTF2(("sock %d: %d UNREAD bytes\n", fd, unread)); + } + } + + /* + * We cannot just set a flag here and let pxtcp_pcb_sent() + * notice and start pulling, because if we are preempted + * before setting the flag and all data in inbuf is ACKed + * there will be no more calls to pxtcp_pcb_sent() to + * notice the flag. + * + * We cannot set a flag and then send a message to make + * sure it noticed, because if it has and it has read all + * data while the message is in transit it will delete + * pxtcp. + * + * In a sense this message is like msg_delete (except we + * ask to pull some data first). + */ + proxy_lwip_post(&pxtcp->msg_inpull); + pxtcp->pmhdl.slot = -1; + return -1; + } + /* NOTREACHED */ + } /* POLLHUP */ +#endif /* HAVE_TCP_POLLHUP */ + + return pxtcp->events; +} + + +/** + * Read data from socket to ringbuf. This may be used both on lwip + * and poll manager threads. + * + * Flag pointed to by pstop is set when further reading is impossible, + * either temporary when buffer is full, or permanently when EOF is + * received. + * + * Returns number of bytes read. NB: EOF is reported as 1! + * + * Returns zero if nothing was read, either because buffer is full, or + * if no data is available (EAGAIN, EINTR &c). + * + * Returns -errno on real socket errors. + */ +static ssize_t +pxtcp_sock_read(struct pxtcp *pxtcp, int *pstop) +{ + IOVEC iov[2]; +#ifndef RT_OS_WINDOWS + struct msghdr mh; +#else + DWORD dwFlags; + int rc; +#endif + int iovlen; + ssize_t nread; + + const size_t sz = pxtcp->inbuf.bufsize; + size_t beg, lim, wrnew; + + *pstop = 0; + +#ifndef RT_OS_WINDOWS + memset(&mh, 0, sizeof(mh)); + mh.msg_iov = iov; +#endif + + beg = pxtcp->inbuf.vacant; + IOVEC_SET_BASE(iov[0], &pxtcp->inbuf.buf[beg]); + + /* lim is the index we can NOT write to */ + lim = pxtcp->inbuf.unacked; + if (lim == 0) { + lim = sz - 1; /* empty slot at the end */ + } + else if (lim == 1) { + lim = sz; /* empty slot at the beginning */ + } + else { + --lim; + } + + if (beg == lim) { + /* + * Buffer is full, stop polling for POLLIN. + * + * pxtcp_pcb_sent() will re-enable POLLIN when guest ACKs + * data, freeing space in the ring buffer. + */ + *pstop = 1; + return 0; + } + + if (beg < lim) { + /* free space in one chunk */ + iovlen = 1; + IOVEC_SET_LEN(iov[0], lim - beg); + } + else { + /* free space in two chunks */ + iovlen = 2; + IOVEC_SET_LEN(iov[0], sz - beg); + IOVEC_SET_BASE(iov[1], &pxtcp->inbuf.buf[0]); + IOVEC_SET_LEN(iov[1], lim); + } + +#ifndef RT_OS_WINDOWS + mh.msg_iovlen = iovlen; + nread = recvmsg(pxtcp->sock, &mh, 0); +#else + dwFlags = 0; + /* We can't assign nread to -1 expecting, that we'll got it back in case of error, + * instead, WSARecv(,,,DWORD *,,,) will rewrite only half of the 64bit value. + */ + nread = 0; + rc = WSARecv(pxtcp->sock, iov, iovlen, (DWORD *)&nread, &dwFlags, NULL, NULL); + if (rc == SOCKET_ERROR) { + warn("pxtcp_sock_read:WSARecv(%d) error:%d nread:%d\n", + pxtcp->sock, + WSAGetLastError(), + nread); + nread = -1; + } + + if (dwFlags) { + warn("pxtcp_sock_read:WSARecv(%d) dwFlags:%x nread:%d\n", + pxtcp->sock, + WSAGetLastError(), + nread); + } +#endif + + if (nread > 0) { + wrnew = beg + nread; + if (wrnew >= sz) { + wrnew -= sz; + } + pxtcp->inbuf.vacant = wrnew; + DPRINTF2(("pxtcp %p: sock %d read %d bytes\n", + (void *)pxtcp, pxtcp->sock, (int)nread)); + return nread; + } + else if (nread == 0) { + *pstop = 1; + pxtcp->inbound_close = 1; + DPRINTF2(("pxtcp %p: sock %d read EOF\n", + (void *)pxtcp, pxtcp->sock)); + return 1; + } + else if (errno == EWOULDBLOCK || errno == EAGAIN || errno == EINTR) { + /* haven't read anything, just return */ + DPRINTF2(("pxtcp %p: sock %d read cancelled\n", + (void *)pxtcp, pxtcp->sock)); + return 0; + } + else { + /* socket error! */ + DPRINTF0(("pxtcp %p: sock %d read errno %d\n", + (void *)pxtcp, pxtcp->sock, errno)); + return -errno; + } +} + + +/** + * Callback from poll manager (pxtcp::msg_inbound) to trigger output + * from ringbuf to guest. + */ +static void +pxtcp_pcb_write_inbound(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + LWIP_ASSERT1(pxtcp != NULL); + + if (pxtcp->pcb == NULL) { + return; + } + + pxtcp_pcb_forward_inbound(pxtcp); +} + + +/** + * tcp_poll() callback + * + * We swtich it on when tcp_write() or tcp_shutdown() fail with + * ERR_MEM to prevent connection from stalling. If there are ACKs or + * more inbound data then pxtcp_pcb_forward_inbound() will be + * triggered again, but if neither happens, tcp_poll() comes to the + * rescue. + */ +static err_t +pxtcp_pcb_poll(void *arg, struct tcp_pcb *pcb) +{ + struct pxtcp *pxtcp = (struct pxtcp *)arg; + LWIP_UNUSED_ARG(pcb); + + DPRINTF2(("%s: pxtcp %p; pcb %p\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb)); + + pxtcp_pcb_forward_inbound(pxtcp); + + /* + * If the last thing holding up deletion of the pxtcp was failed + * tcp_shutdown() and it succeeded, we may be the last callback. + */ + pxtcp_pcb_maybe_deferred_delete(pxtcp); + + return ERR_OK; +} + + +static void +pxtcp_pcb_schedule_poll(struct pxtcp *pxtcp) +{ + tcp_poll(pxtcp->pcb, pxtcp_pcb_poll, 0); +} + + +static void +pxtcp_pcb_cancel_poll(struct pxtcp *pxtcp) +{ + tcp_poll(pxtcp->pcb, NULL, 255); +} + + +/** + * Forward inbound data from ring buffer to the guest. + * + * Scheduled by poll manager thread after it receives more data into + * the ring buffer (we have more data to send). + + * Also called from tcp_sent() callback when guest ACKs some data, + * increasing pcb->snd_buf (we are permitted to send more data). + * + * Also called from tcp_poll() callback if previous attempt to forward + * inbound data failed with ERR_MEM (we need to try again). + */ +static void +pxtcp_pcb_forward_inbound(struct pxtcp *pxtcp) +{ + struct tcp_pcb *pcb; + size_t sndbuf; + size_t beg, lim, sndlim; + size_t toeob, tolim; + size_t nsent; + err_t error; + + LWIP_ASSERT1(pxtcp != NULL); + pcb = pxtcp->pcb; + if (pcb == NULL) { + return; + } + + if (/* __predict_false */ pcb->state < ESTABLISHED) { + /* + * If we have just confirmed accept of this connection, the + * pcb is in SYN_RCVD state and we still haven't received the + * ACK of our SYN. It's only in SYN_RCVD -> ESTABLISHED + * transition that lwip decrements pcb->acked so that that ACK + * is not reported to pxtcp_pcb_sent(). If we send something + * now and immediately close (think "daytime", e.g.) while + * still in SYN_RCVD state, we will move directly to + * FIN_WAIT_1 and when our confirming SYN is ACK'ed lwip will + * report it to pxtcp_pcb_sent(). + */ + DPRINTF2(("forward_inbound: pxtcp %p; pcb %p %s - later...\n", + (void *)pxtcp, (void *)pcb, tcp_debug_state_str(pcb->state))); + return; + } + + + beg = pxtcp->inbuf.unsent; /* private to lwip thread */ + lim = pxtcp->inbuf.vacant; + + if (beg == lim) { + if (pxtcp->inbound_close && !pxtcp->inbound_close_done) { + pxtcp_pcb_forward_inbound_close(pxtcp); + tcp_output(pcb); + return; + } + + /* + * Else, there's no data to send. + * + * If there is free space in the buffer, producer will + * reschedule us as it receives more data and vacant (lim) + * advances. + * + * If buffer is full when all data have been passed to + * tcp_write() but not yet acknowledged, we will advance + * unacked on ACK, freeing some space for producer to write to + * (then see above). + */ + return; + } + + sndbuf = tcp_sndbuf(pcb); + if (sndbuf == 0) { + /* + * Can't send anything now. As guest ACKs some data, TCP will + * call pxtcp_pcb_sent() callback and we will come here again. + */ + return; + } + + nsent = 0; + + /* + * We have three limits to consider: + * - how much data we have in the ringbuf + * - how much data we are allowed to send + * - ringbuf size + */ + toeob = pxtcp->inbuf.bufsize - beg; + if (lim < beg) { /* lim wrapped */ + if (sndbuf < toeob) { /* but we are limited by sndbuf */ + /* so beg is not going to wrap, treat sndbuf as lim */ + lim = beg + sndbuf; /* ... and proceed to the simple case */ + } + else { /* we are limited by the end of the buffer, beg will wrap */ + u8_t maybemore; + if (toeob == sndbuf || lim == 0) { + maybemore = 0; + } + else { + maybemore = TCP_WRITE_FLAG_MORE; + } + + error = tcp_write(pcb, &pxtcp->inbuf.buf[beg], toeob, maybemore); + if (error != ERR_OK) { + goto writeerr; + } + nsent += toeob; + pxtcp->inbuf.unsent = 0; /* wrap */ + + if (maybemore) { + beg = 0; + sndbuf -= toeob; + } + else { + /* we are done sending, but ... */ + goto check_inbound_close; + } + } + } + + LWIP_ASSERT1(beg < lim); + sndlim = beg + sndbuf; + if (lim > sndlim) { + lim = sndlim; + } + tolim = lim - beg; + if (tolim > 0) { + error = tcp_write(pcb, &pxtcp->inbuf.buf[beg], (u16_t)tolim, 0); + if (error != ERR_OK) { + goto writeerr; + } + nsent += tolim; + pxtcp->inbuf.unsent = lim; + } + + check_inbound_close: + if (pxtcp->inbound_close && pxtcp->inbuf.unsent == pxtcp->inbuf.vacant) { + pxtcp_pcb_forward_inbound_close(pxtcp); + } + + DPRINTF2(("forward_inbound: pxtcp %p, pcb %p: sent %d bytes\n", + (void *)pxtcp, (void *)pcb, (int)nsent)); + tcp_output(pcb); + pxtcp_pcb_cancel_poll(pxtcp); + return; + + writeerr: + if (error == ERR_MEM) { + if (nsent > 0) { /* first write succeeded, second failed */ + DPRINTF2(("forward_inbound: pxtcp %p, pcb %p: sent %d bytes only\n", + (void *)pxtcp, (void *)pcb, (int)nsent)); + tcp_output(pcb); + } + DPRINTF(("forward_inbound: pxtcp %p, pcb %p: ERR_MEM\n", + (void *)pxtcp, (void *)pcb)); + pxtcp_pcb_schedule_poll(pxtcp); + } + else { + DPRINTF(("forward_inbound: pxtcp %p, pcb %p: %s\n", + (void *)pxtcp, (void *)pcb, proxy_lwip_strerr(error))); + + /* XXX: We shouldn't get ERR_ARG. Check ERR_CONN conditions early? */ + LWIP_ASSERT1(error == ERR_MEM); + } +} + + +static void +pxtcp_pcb_forward_inbound_close(struct pxtcp *pxtcp) +{ + struct tcp_pcb *pcb; + err_t error; + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->inbound_close); + LWIP_ASSERT1(!pxtcp->inbound_close_done); + LWIP_ASSERT1(pxtcp->inbuf.unsent == pxtcp->inbuf.vacant); + + pcb = pxtcp->pcb; + LWIP_ASSERT1(pcb != NULL); + + DPRINTF(("inbound_close: pxtcp %p; pcb %p: %s\n", + (void *)pxtcp, (void *)pcb, tcp_debug_state_str(pcb->state))); + + error = tcp_shutdown(pcb, /*RX*/ 0, /*TX*/ 1); + if (error != ERR_OK) { + DPRINTF(("inbound_close: pxtcp %p; pcb %p:" + " tcp_shutdown: error=%s\n", + (void *)pxtcp, (void *)pcb, proxy_lwip_strerr(error))); + pxtcp_pcb_schedule_poll(pxtcp); + return; + } + + pxtcp_pcb_cancel_poll(pxtcp); + pxtcp->inbound_close_done = 1; + + + /* + * If we have already done outbound close previously (passive + * close on the pcb), then we must not hold onto a pcb in LAST_ACK + * state since those will be deleted by lwip when that last ack + * comes from the guest. + * + * NB: We do NOT check for deferred delete here, even though we + * have just set one of its conditions, inbound_close_done. We + * let pcb callbacks that called us do that. It's simpler and + * cleaner that way. + */ + if (pxtcp->outbound_close_done && pxtcp_pcb_forward_inbound_done(pxtcp)) { + pxtcp_pcb_dissociate(pxtcp); + } +} + + +/** + * Check that all forwarded inbound data is sent and acked, and that + * inbound close is scheduled (we aren't called back when it's acked). + */ +DECLINLINE(int) +pxtcp_pcb_forward_inbound_done(const struct pxtcp *pxtcp) +{ + return (pxtcp->inbound_close_done /* also implies that all data forwarded */ + && pxtcp->inbuf.unacked == pxtcp->inbuf.unsent); +} + + +/** + * tcp_sent() callback - guest acknowledged len bytes. + * + * We can advance inbuf::unacked index, making more free space in the + * ringbuf and wake up producer on poll manager thread. + * + * We can also try to send more data if we have any since pcb->snd_buf + * was increased and we are now permitted to send more. + */ +static err_t +pxtcp_pcb_sent(void *arg, struct tcp_pcb *pcb, u16_t len) +{ + struct pxtcp *pxtcp = (struct pxtcp *)arg; + size_t unacked; + + LWIP_ASSERT1(pxtcp != NULL); + LWIP_ASSERT1(pxtcp->pcb == pcb); + LWIP_ASSERT1(pcb->callback_arg == pxtcp); + LWIP_UNUSED_ARG(pcb); /* only in assert */ + + DPRINTF2(("%s: pxtcp %p; pcb %p: +%d ACKed:" + " unacked %d, unsent %d, vacant %d\n", + __func__, (void *)pxtcp, (void *)pcb, (int)len, + (int)pxtcp->inbuf.unacked, + (int)pxtcp->inbuf.unsent, + (int)pxtcp->inbuf.vacant)); + + if (/* __predict_false */ len == 0) { + /* we are notified to start pulling */ + LWIP_ASSERT1(pxtcp->outbound_close_done); + LWIP_ASSERT1(!pxtcp->inbound_close); + LWIP_ASSERT1(pxtcp->inbound_pull); + + unacked = pxtcp->inbuf.unacked; + } + else { + /* + * Advance unacked index. Guest acknowledged the data, so it + * won't be needed again for potential retransmits. + */ + unacked = pxtcp->inbuf.unacked + len; + if (unacked > pxtcp->inbuf.bufsize) { + unacked -= pxtcp->inbuf.bufsize; + } + pxtcp->inbuf.unacked = unacked; + } + + /* arrange for more inbound data */ + if (!pxtcp->inbound_close) { + if (!pxtcp->inbound_pull) { + /* wake up producer, in case it has stopped polling for POLLIN */ + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_POLLIN, pxtcp); +#ifdef RT_OS_WINDOWS + /** + * We have't got enought room in ring buffer to read atm, + * but we don't want to lose notification from WSAW4ME when + * space would be available, so we reset event with empty recv + */ + recv(pxtcp->sock, NULL, 0, 0); +#endif + } + else { + ssize_t nread; + int stop_pollin; /* ignored */ + + nread = pxtcp_sock_read(pxtcp, &stop_pollin); + + if (nread < 0) { + int sockerr = -(int)nread; + LWIP_UNUSED_ARG(sockerr); + DPRINTF0(("%s: sock %d: errno %d\n", + __func__, pxtcp->sock, sockerr)); + + /* + * Since we are pulling, pxtcp is no longer registered + * with poll manager so we can kill it directly. + */ + pxtcp_pcb_reset_pxtcp(pxtcp); + return ERR_ABRT; + } + } + } + + /* forward more data if we can */ + if (!pxtcp->inbound_close_done) { + pxtcp_pcb_forward_inbound(pxtcp); + + /* + * NB: we might have dissociated from a pcb that transitioned + * to LAST_ACK state, so don't refer to pcb below. + */ + } + + + /* have we got all the acks? */ + if (pxtcp->inbound_close /* no more new data */ + && pxtcp->inbuf.unsent == pxtcp->inbuf.vacant /* all data is sent */ + && unacked == pxtcp->inbuf.unsent) /* ... and is acked */ + { + char *buf; + + DPRINTF(("%s: pxtcp %p; pcb %p; all data ACKed\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb)); + + /* no more retransmits, so buf is not needed */ + buf = pxtcp->inbuf.buf; + pxtcp->inbuf.buf = NULL; + free(buf); + + /* no more acks, so no more callbacks */ + if (pxtcp->pcb != NULL) { + tcp_sent(pxtcp->pcb, NULL); + } + + /* + * We may be the last callback for this pcb if we have also + * successfully forwarded inbound_close. + */ + pxtcp_pcb_maybe_deferred_delete(pxtcp); + } + + return ERR_OK; +} + + +/** + * Callback from poll manager (pxtcp::msg_inpull) to switch + * pxtcp_pcb_sent() to actively pull the last bits of input. See + * POLLHUP comment in pxtcp_pmgr_pump(). + * + * pxtcp::sock is deregistered from poll manager after this callback + * is scheduled. + */ +static void +pxtcp_pcb_pull_inbound(void *ctx) +{ + struct pxtcp *pxtcp = (struct pxtcp *)ctx; + LWIP_ASSERT1(pxtcp != NULL); + + if (pxtcp->pcb == NULL) { + DPRINTF(("%s: pxtcp %p: PCB IS GONE\n", __func__, (void *)pxtcp)); + pxtcp_pcb_reset_pxtcp(pxtcp); + return; + } + + DPRINTF(("%s: pxtcp %p: pcb %p\n", + __func__, (void *)pxtcp, (void *)pxtcp->pcb)); + pxtcp->inbound_pull = 1; + pxtcp->deferred_delete = 1; + pxtcp_pcb_sent(pxtcp, pxtcp->pcb, 0); +} + + +/** + * tcp_err() callback. + * + * pcb is not passed to this callback since it may be already + * deallocated by the stack, but we can't do anything useful with it + * anyway since connection is gone. + */ +static void +pxtcp_pcb_err(void *arg, err_t error) +{ + struct pxtcp *pxtcp = (struct pxtcp *)arg; + LWIP_ASSERT1(pxtcp != NULL); + + /* + * ERR_CLSD is special - it is reported here when: + * + * . guest has already half-closed + * . we send FIN to guest when external half-closes + * . guest acks that FIN + * + * Since connection is closed but receive has been already closed + * lwip can only report this via tcp_err. At this point the pcb + * is still alive, so we can peek at it if need be. + * + * The interesting twist is when the ACK from guest that akcs our + * FIN also acks some data. In this scenario lwip will NOT call + * tcp_sent() callback with the ACK for that last bit of data but + * instead will call tcp_err with ERR_CLSD right away. Since that + * ACK also acknowledges all the data, we should run some of + * pxtcp_pcb_sent() logic here. + */ + if (error == ERR_CLSD) { + struct tcp_pcb *pcb = pxtcp->pcb; /* still alive */ + + DPRINTF2(("ERR_CLSD: pxtcp %p; pcb %p:" + " pcb->acked %d;" + " unacked %d, unsent %d, vacant %d\n", + (void *)pxtcp, (void *)pcb, + pcb->acked, + (int)pxtcp->inbuf.unacked, + (int)pxtcp->inbuf.unsent, + (int)pxtcp->inbuf.vacant)); + + LWIP_ASSERT1(pxtcp->pcb == pcb); + LWIP_ASSERT1(pcb->callback_arg == pxtcp); + + if (pcb->acked > 0) { + pxtcp_pcb_sent(pxtcp, pcb, pcb->acked); + } + return; + } + + DPRINTF0(("tcp_err: pxtcp=%p, error=%s\n", + (void *)pxtcp, proxy_lwip_strerr(error))); + + pxtcp->pcb = NULL; /* pcb is gone */ + if (pxtcp->deferred_delete) { + pxtcp_pcb_reset_pxtcp(pxtcp); + } + else { + pxtcp_chan_send_weak(POLLMGR_CHAN_PXTCP_RESET, pxtcp); + } +} |