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author | Daniel Stenberg <daniel@haxx.se> | 2003-10-07 21:54:04 +0000 |
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committer | Daniel Stenberg <daniel@haxx.se> | 2003-10-07 21:54:04 +0000 |
commit | 0436fbe226ca8ea71a751f4a86a228632e5cbc63 (patch) | |
tree | 5cf6478e89608a8000bd36014ba4032bcc9c0528 /ares/ares_gethostbyname.c | |
parent | 6494889e3ba6b1432258f0a8ed402723607cff21 (diff) | |
download | curl-0436fbe226ca8ea71a751f4a86a228632e5cbc63.tar.gz |
ares 1.1.1 with collected applied patches
Diffstat (limited to 'ares/ares_gethostbyname.c')
-rw-r--r-- | ares/ares_gethostbyname.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/ares/ares_gethostbyname.c b/ares/ares_gethostbyname.c new file mode 100644 index 000000000..1e3755a6e --- /dev/null +++ b/ares/ares_gethostbyname.c @@ -0,0 +1,297 @@ +/* Copyright 1998 by the Massachusetts Institute of Technology. + * + * Permission to use, copy, modify, and distribute this + * software and its documentation for any purpose and without + * fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright + * notice and this permission notice appear in supporting + * documentation, and that the name of M.I.T. not be used in + * advertising or publicity pertaining to distribution of the + * software without specific, written prior permission. + * M.I.T. makes no representations about the suitability of + * this software for any purpose. It is provided "as is" + * without express or implied warranty. + */ + +static const char rcsid[] = "$Id$"; + +#include <sys/types.h> + +#ifdef WIN32 +#include "nameser.h" +#else +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <netdb.h> +#include <arpa/nameser.h> +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <ctype.h> +#include "ares.h" +#include "ares_private.h" + +struct host_query { + /* Arguments passed to ares_gethostbyname() */ + ares_channel channel; + char *name; + ares_host_callback callback; + void *arg; + + const char *remaining_lookups; +}; + +static void next_lookup(struct host_query *hquery); +static void host_callback(void *arg, int status, unsigned char *abuf, + int alen); +static void end_hquery(struct host_query *hquery, int status, + struct hostent *host); +static int fake_hostent(const char *name, ares_host_callback callback, + void *arg); +static int file_lookup(const char *name, struct hostent **host); +static void sort_addresses(struct hostent *host, struct apattern *sortlist, + int nsort); +static int get_address_index(struct in_addr *addr, struct apattern *sortlist, + int nsort); + +void ares_gethostbyname(ares_channel channel, const char *name, int family, + ares_host_callback callback, void *arg) +{ + struct host_query *hquery; + + /* Right now we only know how to look up Internet addresses. */ + if (family != AF_INET) + { + callback(arg, ARES_ENOTIMP, NULL); + return; + } + + if (fake_hostent(name, callback, arg)) + return; + + /* Allocate and fill in the host query structure. */ + hquery = malloc(sizeof(struct host_query)); + if (!hquery) + { + callback(arg, ARES_ENOMEM, NULL); + return; + } + hquery->channel = channel; + hquery->name = strdup(name); + if (!hquery->name) + { + free(hquery); + callback(arg, ARES_ENOMEM, NULL); + return; + } + hquery->callback = callback; + hquery->arg = arg; + hquery->remaining_lookups = channel->lookups; + + /* Start performing lookups according to channel->lookups. */ + next_lookup(hquery); +} + +static void next_lookup(struct host_query *hquery) +{ + int status; + const char *p; + struct hostent *host; + + for (p = hquery->remaining_lookups; *p; p++) + { + switch (*p) + { + case 'b': + /* DNS lookup */ + hquery->remaining_lookups = p + 1; + ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback, + hquery); + return; + + case 'f': + /* Host file lookup */ + status = file_lookup(hquery->name, &host); + if (status != ARES_ENOTFOUND) + { + end_hquery(hquery, status, host); + return; + } + break; + } + } + end_hquery(hquery, ARES_ENOTFOUND, NULL); +} + +static void host_callback(void *arg, int status, unsigned char *abuf, int alen) +{ + struct host_query *hquery = (struct host_query *) arg; + ares_channel channel = hquery->channel; + struct hostent *host; + + if (status == ARES_SUCCESS) + { + status = ares_parse_a_reply(abuf, alen, &host); + if (host && channel->nsort) + sort_addresses(host, channel->sortlist, channel->nsort); + end_hquery(hquery, status, host); + } + else if (status == ARES_EDESTRUCTION) + end_hquery(hquery, status, NULL); + else + next_lookup(hquery); +} + +static void end_hquery(struct host_query *hquery, int status, + struct hostent *host) +{ + hquery->callback(hquery->arg, status, host); + if (host) + ares_free_hostent(host); + free(hquery->name); + free(hquery); +} + +/* If the name looks like an IP address, fake up a host entry, end the + * query immediately, and return true. Otherwise return false. + */ +static int fake_hostent(const char *name, ares_host_callback callback, + void *arg) +{ + struct in_addr addr; + struct hostent hostent; + const char *p; + char *aliases[1] = { NULL }; + char *addrs[2]; + + /* It only looks like an IP address if it's all numbers and dots. */ + for (p = name; *p; p++) + { + if (!isdigit((unsigned char)*p) && *p != '.') + return 0; + } + + /* It also only looks like an IP address if it's non-zero-length and + * doesn't end with a dot. + */ + if (p == name || *(p - 1) == '.') + return 0; + + /* It looks like an IP address. Figure out what IP address it is. */ + addr.s_addr = inet_addr(name); + if (addr.s_addr == INADDR_NONE) + { + callback(arg, ARES_EBADNAME, NULL); + return 1; + } + + /* Duplicate the name, to avoid a constness violation. */ + hostent.h_name = strdup(name); + if (!hostent.h_name) + { + callback(arg, ARES_ENOMEM, NULL); + return 1; + } + + /* Fill in the rest of the host structure and terminate the query. */ + addrs[0] = (char *) &addr; + addrs[1] = NULL; + hostent.h_aliases = aliases; + hostent.h_addrtype = AF_INET; + hostent.h_length = sizeof(struct in_addr); + hostent.h_addr_list = addrs; + callback(arg, ARES_SUCCESS, &hostent); + + free(hostent.h_name); + return 1; +} + +static int file_lookup(const char *name, struct hostent **host) +{ + FILE *fp; + char **alias; + int status; + +#ifdef WIN32 + + char PATH_HOSTS[MAX_PATH]; + if (IsNT) { + GetSystemDirectory(PATH_HOSTS, MAX_PATH); + strcat(PATH_HOSTS, PATH_HOSTS_NT); + } else { + GetWindowsDirectory(PATH_HOSTS, MAX_PATH); + strcat(PATH_HOSTS, PATH_HOSTS_9X); + } + +#endif + + fp = fopen(PATH_HOSTS, "r"); + if (!fp) + return ARES_ENOTFOUND; + + while ((status = ares__get_hostent(fp, host)) == ARES_SUCCESS) + { + if (strcasecmp((*host)->h_name, name) == 0) + break; + for (alias = (*host)->h_aliases; *alias; alias++) + { + if (strcasecmp(*alias, name) == 0) + break; + } + if (*alias) + break; + ares_free_hostent(*host); + } + fclose(fp); + if (status == ARES_EOF) + status = ARES_ENOTFOUND; + if (status != ARES_SUCCESS) + *host = NULL; + return status; +} + +static void sort_addresses(struct hostent *host, struct apattern *sortlist, + int nsort) +{ + struct in_addr a1, a2; + int i1, i2, ind1, ind2; + + /* This is a simple insertion sort, not optimized at all. i1 walks + * through the address list, with the loop invariant that everything + * to the left of i1 is sorted. In the loop body, the value at i1 is moved + * back through the list (via i2) until it is in sorted order. + */ + for (i1 = 0; host->h_addr_list[i1]; i1++) + { + memcpy(&a1, host->h_addr_list[i1], sizeof(struct in_addr)); + ind1 = get_address_index(&a1, sortlist, nsort); + for (i2 = i1 - 1; i2 >= 0; i2--) + { + memcpy(&a2, host->h_addr_list[i2], sizeof(struct in_addr)); + ind2 = get_address_index(&a2, sortlist, nsort); + if (ind2 <= ind1) + break; + memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct in_addr)); + } + memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct in_addr)); + } +} + +/* Find the first entry in sortlist which matches addr. Return nsort + * if none of them match. + */ +static int get_address_index(struct in_addr *addr, struct apattern *sortlist, + int nsort) +{ + int i; + + for (i = 0; i < nsort; i++) + { + if ((addr->s_addr & sortlist[i].mask.s_addr) == sortlist[i].addr.s_addr) + break; + } + return i; +} |