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Diffstat (limited to 'lib/altsvc.c')
| -rw-r--r-- | lib/altsvc.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/lib/altsvc.c b/lib/altsvc.c new file mode 100644 index 000000000..97cdc7b8a --- /dev/null +++ b/lib/altsvc.c @@ -0,0 +1,569 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 2019, Daniel Stenberg, <daniel@haxx.se>, et al. + * + * This software is licensed as described in the file COPYING, which + * you should have received as part of this distribution. The terms + * are also available at https://curl.haxx.se/docs/copyright.html. + * + * You may opt to use, copy, modify, merge, publish, distribute and/or sell + * copies of the Software, and permit persons to whom the Software is + * furnished to do so, under the terms of the COPYING file. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ***************************************************************************/ +/* + * The Alt-Svc: header is defined in RFC 7838: + * https://tools.ietf.org/html/rfc7838 + */ +#include "curl_setup.h" + +#if !defined(CURL_DISABLE_HTTP) && defined(USE_ALTSVC) +#include <curl/curl.h> +#include "urldata.h" +#include "altsvc.h" +#include "cookie.h" /* for Curl_get_line() */ +#include "strcase.h" +#include "parsedate.h" +#include "sendf.h" +#include "warnless.h" + +/* The last 3 #include files should be in this order */ +#include "curl_printf.h" +#include "curl_memory.h" +#include "memdebug.h" + +#define MAX_ALTSVC_LINE 4095 +#define MAX_ALTSVC_DATELENSTR "64" +#define MAX_ALTSVC_DATELEN 64 +#define MAX_ALTSVC_HOSTLENSTR "512" +#define MAX_ALTSVC_HOSTLEN 512 +#define MAX_ALTSVC_ALPNLENSTR "10" +#define MAX_ALTSVC_ALPNLEN 10 + +static enum alpnid alpn2alpnid(char *name) +{ + if(strcasecompare(name, "h1")) + return ALPN_h1; + if(strcasecompare(name, "h2")) + return ALPN_h2; + if(strcasecompare(name, "h2c")) + return ALPN_h2c; + if(strcasecompare(name, "h3")) + return ALPN_h3; + return ALPN_none; /* unknown, probably rubbish input */ +} + +/* Given the ALPN ID, return the name */ +const char *Curl_alpnid2str(enum alpnid id) +{ + switch(id) { + case ALPN_h1: + return "h1"; + case ALPN_h2: + return "h2"; + case ALPN_h2c: + return "h2c"; + case ALPN_h3: + return "h3"; + default: + return ""; /* bad */ + } +} + + +static void altsvc_free(struct altsvc *as) +{ + free(as->srchost); + free(as->dsthost); + free(as); +} + +static struct altsvc *altsvc_createid(const char *srchost, + const char *dsthost, + enum alpnid srcalpnid, + enum alpnid dstalpnid, + unsigned int srcport, + unsigned int dstport) +{ + struct altsvc *as = calloc(sizeof(struct altsvc), 1); + if(!as) + return NULL; + + as->srchost = strdup(srchost); + if(!as->srchost) + goto error; + as->dsthost = strdup(dsthost); + if(!as->dsthost) + goto error; + + as->srcalpnid = srcalpnid; + as->dstalpnid = dstalpnid; + as->srcport = curlx_ultous(srcport); + as->dstport = curlx_ultous(dstport); + + return as; + error: + altsvc_free(as); + return NULL; +} + +static struct altsvc *altsvc_create(char *srchost, + char *dsthost, + char *srcalpn, + char *dstalpn, + unsigned int srcport, + unsigned int dstport) +{ + enum alpnid dstalpnid = alpn2alpnid(dstalpn); + enum alpnid srcalpnid = alpn2alpnid(srcalpn); + if(!srcalpnid || !dstalpnid) + return NULL; + return altsvc_createid(srchost, dsthost, srcalpnid, dstalpnid, + srcport, dstport); +} + +/* only returns SERIOUS errors */ +static CURLcode altsvc_add(struct altsvcinfo *asi, char *line) +{ + /* Example line: + h2 example.com 443 h3 shiny.example.com 8443 "20191231 10:00:00" 1 + */ + char srchost[MAX_ALTSVC_HOSTLEN + 1]; + char dsthost[MAX_ALTSVC_HOSTLEN + 1]; + char srcalpn[MAX_ALTSVC_ALPNLEN + 1]; + char dstalpn[MAX_ALTSVC_ALPNLEN + 1]; + char date[MAX_ALTSVC_DATELEN + 1]; + unsigned int srcport; + unsigned int dstport; + unsigned int prio; + unsigned int persist; + int rc; + + rc = sscanf(line, + "%" MAX_ALTSVC_ALPNLENSTR "s %" MAX_ALTSVC_HOSTLENSTR "s %u " + "%" MAX_ALTSVC_ALPNLENSTR "s %" MAX_ALTSVC_HOSTLENSTR "s %u " + "\"%" MAX_ALTSVC_DATELENSTR "[^\"]\" %u %u", + srcalpn, srchost, &srcport, + dstalpn, dsthost, &dstport, + date, &persist, &prio); + if(9 == rc) { + struct altsvc *as; + time_t expires = curl_getdate(date, NULL); + as = altsvc_create(srchost, dsthost, srcalpn, dstalpn, srcport, dstport); + if(as) { + as->expires = expires; + as->prio = prio; + as->persist = persist ? 1 : 0; + Curl_llist_insert_next(&asi->list, asi->list.tail, as, &as->node); + asi->num++; /* one more entry */ + } + } + + return CURLE_OK; +} + +/* + * Load alt-svc entries from the given file. The text based line-oriented file + * format is documented here: + * https://github.com/curl/curl/wiki/QUIC-implementation + * + * This function only returns error on major problems that prevents alt-svc + * handling to work completely. It will ignore individual syntactical errors + * etc. + */ +static CURLcode altsvc_load(struct altsvcinfo *asi, const char *file) +{ + CURLcode result = CURLE_OK; + char *line = NULL; + FILE *fp = fopen(file, FOPEN_READTEXT); + if(fp) { + line = malloc(MAX_ALTSVC_LINE); + if(!line) + goto fail; + while(Curl_get_line(line, MAX_ALTSVC_LINE, fp)) { + char *lineptr = line; + while(*lineptr && ISBLANK(*lineptr)) + lineptr++; + if(*lineptr == '#') + /* skip commented lines */ + continue; + + altsvc_add(asi, lineptr); + } + free(line); /* free the line buffer */ + fclose(fp); + } + return result; + + fail: + free(line); + fclose(fp); + return CURLE_OUT_OF_MEMORY; +} + +/* + * Write this single altsvc entry to a single output line + */ + +static CURLcode altsvc_out(struct altsvc *as, FILE *fp) +{ + struct tm stamp; + Curl_gmtime(as->expires, &stamp); + + fprintf(fp, + "%s %s %u " + "%s %s %u " + "\"%d%02d%02d " + "%02d:%02d:%02d\" " + "%u %d\n", + Curl_alpnid2str(as->srcalpnid), as->srchost, as->srcport, + Curl_alpnid2str(as->dstalpnid), as->dsthost, as->dstport, + stamp.tm_year + 1900, stamp.tm_mon + 1, stamp.tm_mday, + stamp.tm_hour, stamp.tm_min, stamp.tm_sec, + as->persist, as->prio); + return CURLE_OK; +} + +/* ---- library-wide functions below ---- */ + +/* + * Curl_altsvc_init() creates a new altsvc cache. + * It returns the new instance or NULL if something goes wrong. + */ +struct altsvcinfo *Curl_altsvc_init(void) +{ + struct altsvcinfo *asi = calloc(sizeof(struct altsvcinfo), 1); + if(!asi) + return NULL; + Curl_llist_init(&asi->list, NULL); + + /* set default behavior */ + asi->flags = CURLALTSVC_H1 +#ifdef USE_NGHTTP2 + | CURLALTSVC_H2 +#endif +#ifdef USE_HTTP3 + /* TODO: adjust when known */ + | CURLALTSVC_H3 +#endif + ; + return asi; +} + +/* + * Curl_altsvc_load() loads alt-svc from file. + */ +CURLcode Curl_altsvc_load(struct altsvcinfo *asi, const char *file) +{ + CURLcode result; + DEBUGASSERT(asi); + result = altsvc_load(asi, file); + return result; +} + +/* + * Curl_altsvc_ctrl() passes on the external bitmask. + */ +CURLcode Curl_altsvc_ctrl(struct altsvcinfo *asi, const long ctrl) +{ + DEBUGASSERT(asi); + if(!ctrl) + /* unexpected */ + return CURLE_BAD_FUNCTION_ARGUMENT; + asi->flags = ctrl; + return CURLE_OK; +} + +/* + * Curl_altsvc_cleanup() frees an altsvc cache instance and all associated + * resources. + */ +void Curl_altsvc_cleanup(struct altsvcinfo *altsvc) +{ + struct curl_llist_element *e; + struct curl_llist_element *n; + if(altsvc) { + for(e = altsvc->list.head; e; e = n) { + struct altsvc *as = e->ptr; + n = e->next; + altsvc_free(as); + } + free(altsvc); + } +} + +/* + * Curl_altsvc_save() writes the altsvc cache to a file. + */ +CURLcode Curl_altsvc_save(struct altsvcinfo *altsvc, const char *file) +{ + struct curl_llist_element *e; + struct curl_llist_element *n; + CURLcode result = CURLE_OK; + FILE *out; + + if(!altsvc) + /* no cache activated */ + return CURLE_OK; + + if((altsvc->flags & CURLALTSVC_READONLYFILE) || !file[0]) + /* marked as read-only or zero length file name */ + return CURLE_OK; + out = fopen(file, FOPEN_WRITETEXT); + if(!out) + return CURLE_WRITE_ERROR; + fputs("# Your alt-svc cache. https://curl.haxx.se/docs/alt-svc.html\n" + "# This file was generated by libcurl! Edit at your own risk.\n", + out); + for(e = altsvc->list.head; e; e = n) { + struct altsvc *as = e->ptr; + n = e->next; + result = altsvc_out(as, out); + if(result) + break; + } + fclose(out); + return result; +} + +static CURLcode getalnum(const char **ptr, char *alpnbuf, size_t buflen) +{ + size_t len; + const char *protop; + const char *p = *ptr; + while(*p && ISBLANK(*p)) + p++; + protop = p; + while(*p && ISALNUM(*p)) + p++; + len = p - protop; + + if(!len || (len >= buflen)) + return CURLE_BAD_FUNCTION_ARGUMENT; /* TODO: improve error code */ + memcpy(alpnbuf, protop, len); + alpnbuf[len] = 0; + *ptr = p; + return CURLE_OK; +} + +/* altsvc_flush() removes all alternatives for this source origin from the + list */ +static void altsvc_flush(struct altsvcinfo *asi, enum alpnid srcalpnid, + const char *srchost, unsigned short srcport) +{ + struct curl_llist_element *e; + struct curl_llist_element *n; + for(e = asi->list.head; e; e = n) { + struct altsvc *as = e->ptr; + n = e->next; + if((srcalpnid == as->srcalpnid) && + (srcport == as->srcport) && + strcasecompare(srchost, as->srchost)) { + Curl_llist_remove(&asi->list, e, NULL); + altsvc_free(as); + asi->num--; + } + } +} + +#ifdef DEBUGBUILD +/* to play well with debug builds, we can *set* a fixed time this will + return */ +static time_t debugtime(void *unused) +{ + char *timestr = getenv("CURL_TIME"); + (void)unused; + if(timestr) { + unsigned long val = strtol(timestr, NULL, 10); + return (time_t)val; + } + return time(NULL); +} +#define time(x) debugtime(x) +#endif + +/* + * Curl_altsvc_parse() takes an incoming alt-svc response header and stores + * the data correctly in the cache. + * + * 'value' points to the header *value*. That's contents to the right of the + * header name. + */ +CURLcode Curl_altsvc_parse(struct Curl_easy *data, + struct altsvcinfo *asi, const char *value, + enum alpnid srcalpnid, const char *srchost, + unsigned short srcport) +{ + const char *p = value; + size_t len; + enum alpnid dstalpnid = srcalpnid; /* the same by default */ + char namebuf[MAX_ALTSVC_HOSTLEN] = ""; + char alpnbuf[MAX_ALTSVC_ALPNLEN] = ""; + struct altsvc *as; + unsigned short dstport = srcport; /* the same by default */ + const char *semip; + time_t maxage = 24 * 3600; /* default is 24 hours */ + bool persist = FALSE; + CURLcode result = getalnum(&p, alpnbuf, sizeof(alpnbuf)); + if(result) + return result; + + DEBUGASSERT(asi); + + /* Flush all cached alternatives for this source origin, if any */ + altsvc_flush(asi, srcalpnid, srchost, srcport); + + /* "clear" is a magic keyword */ + if(strcasecompare(alpnbuf, "clear")) { + /* TODO: clear whatever it is it should clear */ + return CURLE_OK; + } + + /* The 'ma' and 'persist' flags are annoyingly meant for all alternatives + but are set after the list on the line. Scan for the semicolons and get + those fields first! */ + semip = p; + do { + semip = strchr(semip, ';'); + if(semip) { + char option[32]; + unsigned long num; + char *end_ptr; + semip++; /* pass the semicolon */ + result = getalnum(&semip, option, sizeof(option)); + if(result) + break; + while(*semip && ISBLANK(*semip)) + semip++; + if(*semip != '=') + continue; + semip++; + num = strtoul(semip, &end_ptr, 10); + if(num < ULONG_MAX) { + if(strcasecompare("ma", option)) + maxage = num; + else if(strcasecompare("persist", option) && (num == 1)) + persist = TRUE; + } + semip = end_ptr; + } + } while(semip); + + do { + if(*p == '=') { + /* [protocol]="[host][:port]" */ + dstalpnid = alpn2alpnid(alpnbuf); + if(!dstalpnid) { + infof(data, "Unknown alt-svc protocol \"%s\", ignoring...\n", alpnbuf); + return CURLE_OK; + } + p++; + if(*p == '\"') { + const char *dsthost; + p++; + if(*p != ':') { + /* host name starts here */ + const char *hostp = p; + while(*p && (ISALNUM(*p) || (*p == '.') || (*p == '-'))) + p++; + len = p - hostp; + if(!len || (len >= MAX_ALTSVC_HOSTLEN)) + return CURLE_BAD_FUNCTION_ARGUMENT; /* TODO: improve error code */ + memcpy(namebuf, hostp, len); + namebuf[len] = 0; + dsthost = namebuf; + } + else { + /* no destination name, use source host */ + dsthost = srchost; + } + if(*p == ':') { + /* a port number */ + char *end_ptr; + unsigned long port = strtoul(++p, &end_ptr, 10); + if(port > USHRT_MAX || end_ptr == p || *end_ptr != '\"') { + infof(data, "Unknown alt-svc port number, ignoring...\n"); + return CURLE_OK; + } + p = end_ptr; + dstport = curlx_ultous(port); + } + if(*p++ != '\"') + return CURLE_BAD_FUNCTION_ARGUMENT; + as = altsvc_createid(srchost, dsthost, + srcalpnid, dstalpnid, + srcport, dstport); + if(as) { + /* TODO: the expires time also needs to take the Age: value (if any) + into account. [See RFC 7838 section 3.1] */ + as->expires = maxage + time(NULL); + as->persist = persist; + Curl_llist_insert_next(&asi->list, asi->list.tail, as, &as->node); + asi->num++; /* one more entry */ + infof(data, "Added alt-svc: %s:%d over %s\n", dsthost, dstport, + Curl_alpnid2str(dstalpnid)); + } + } + /* after the double quote there can be a comma if there's another + string or a semicolon if no more */ + if(*p == ',') { + /* comma means another alternative is presented */ + p++; + result = getalnum(&p, alpnbuf, sizeof(alpnbuf)); + if(result) + /* failed to parse, but since we alredy did at least one host we + return OK */ + return CURLE_OK; + } + } + } while(*p && (*p != ';') && (*p != '\n') && (*p != '\r')); + + return CURLE_OK; +} + +/* + * Return TRUE on a match + */ +bool Curl_altsvc_lookup(struct altsvcinfo *asi, + enum alpnid srcalpnid, const char *srchost, + int srcport, + enum alpnid *dstalpnid, const char **dsthost, + int *dstport) +{ + struct curl_llist_element *e; + struct curl_llist_element *n; + time_t now = time(NULL); + DEBUGASSERT(asi); + DEBUGASSERT(srchost); + DEBUGASSERT(dsthost); + + for(e = asi->list.head; e; e = n) { + struct altsvc *as = e->ptr; + n = e->next; + if(as->expires < now) { + /* an expired entry, remove */ + altsvc_free(as); + continue; + } + if((as->srcalpnid == srcalpnid) && + strcasecompare(as->srchost, srchost) && + as->srcport == srcport) { + /* match */ + *dstalpnid = as->dstalpnid; + *dsthost = as->dsthost; + *dstport = as->dstport; + return TRUE; + } + } + return FALSE; +} + +#endif /* CURL_DISABLE_HTTP || USE_ALTSVC */ |