diff options
Diffstat (limited to 'src/qmail-smtpc/dns.c')
| -rw-r--r-- | src/qmail-smtpc/dns.c | 378 |
1 files changed, 258 insertions, 120 deletions
diff --git a/src/qmail-smtpc/dns.c b/src/qmail-smtpc/dns.c index 52ec552..90aade4 100644 --- a/src/qmail-smtpc/dns.c +++ b/src/qmail-smtpc/dns.c @@ -1,19 +1,43 @@ /* ISC license. */ #include <string.h> +#include <stdint.h> +#include <limits.h> #include <stdlib.h> +#include <errno.h> #include <skalibs/tai.h> #include <skalibs/stralloc.h> #include <skalibs/genalloc.h> +#include <skalibs/iopause.h> #include <skalibs/ip46.h> #include <skalibs/random.h> #include <s6-dns/s6dns.h> +#include <s6-dns/skadns.h> #include "qmailr.h" #include "qmail-smtpc.h" +typedef struct cnameinfo_s cnameinfo, *cnameinfo_ref ; +struct cnameinfo_s +{ + stralloc sa ; + size_t atpos ; + uint16_t id ; + uint16_t count ; +} ; + +typedef struct mxipinfo_s mxipinfo, mxipinfo_ref ; +struct mxipinfo_s +{ + stralloc ip4 ; + stralloc ip6 ; + uint16_t id4 ; + uint16_t id6 ; +} ; +#define MXIPINFO_ZERO { .ip4 = STRALLOC_ZERO, .ip6 = STRALLOC_ZERO, .id4 = UINT16_MAX, .id6 = UINT16_MAX } + static int mx_cmp (void const *a, void const *b) { s6dns_message_rr_mx_t const *aa = a ; @@ -21,157 +45,271 @@ static int mx_cmp (void const *a, void const *b) return aa->preference < bb-> preference ? -1 : aa->preference > bb->preference ; } -void dns_init (void) +static unsigned int use_host_as_mx (skadns_t *a, char const *host, genalloc *mxip, tain const *deadline) { - if (!s6dns_init_options(0)) qmailr_tempsys("Unable to init DNS") ; + unsigned int newreqs = 0 ; + mxipinfo info = MXIPINFO_ZERO ; + s6dns_domain_t q ; + if (!s6dns_domain_fromstring_noqualify_encode(&q, host, strlen(host))) + qmailr_tempsys("Unable to DNS-encode host domain") ; + if (!skadns_send_g(a, &info.id4, &q, S6DNS_T_A, deadline, deadline)) + qmailr_tempsys("Unable to send A DNS query") ; + newreqs++ ; +#ifdef SKALIBS_IPV6_ENABLED + if (!skadns_send_g(a, &info.id6, &q, S6DNS_T_AAAA, deadline, deadline)) + qmailr_tempsys("Unable to send AAAA DNS query") ; + newreqs++ ; +#endif + if (!genalloc_catb(mxipinfo, mxip, &info, 1)) dienomem() ; + return newreqs ; } -void dns_canon (char const *host, char const *const *recip, unsigned int n, size_t *recippos, genalloc *mxpos, stralloc *storage) -{ - genalloc mx = GENALLOC_ZERO ; /* s6dns_message_rr_mx_t */ - size_t atpos[n] ; - s6dns_dpag_t cnames[n] ; - s6dns_resolve_t info[n + !!mxpos] ; + /* + The point of this monster here is to do all the DNS resolutions in parallel, + to avoid compounding network latency. One of the many things that could never + be done by patching qmail-remote. + 1 sender + n-1 recipients are given in eaddr. + - loop around CNAME until we get the canonical name, for the n eaddrs + - either lookup the MX for the host then find all the A and AAAAs of all the MXes, + or get the A and AAAAs of the host directly (if smtproutes) + - do not keep the As and AAAAs listed in ipme + - sort the set of IPs by MX preference + When done, quote all the boxnames in eaddr. + Shove everything in storage and return the indices: + in eaddrpos for sender+recipients, in mxipind for the IPs to connect to. - for (unsigned int i = 0 ; i < n ; i++) - { - char const *at = strrchr(recip[i], '@') ; - if (!at) qmailr_perm("Invalid recipient") ; - atpos[i] = at - recip[i] ; - if (!s6dns_domain_fromstring_noqualify_encode(&info[i].q, at+1, strlen(at+1))) - qmailr_tempsys("Unable to DNS-encode recipient domain") ; - cnames[i].ds = genalloc_zero ; - cnames[i].rtype = S6DNS_T_CNAME ; - info[i].qtype = S6DNS_T_CNAME ; - info[i].options = S6DNS_O_RECURSIVE ; - info[i].deadline = tain_infinite ; - info[i].parsefunc = &s6dns_message_parse_answer_domain ; - info[i].data = cnames + i ; - } - if (!s6dns_domain_fromstring_noqualify_encode(&info[n].q, host, strlen(host))) - qmailr_tempsys("Unable to DNS-encode recipient domain") ; + Also, fuck DNS for requiring so many small allocations and data copies. - if (mxpos) - { - info[n].qtype = S6DNS_T_MX ; - info[n].options = S6DNS_O_RECURSIVE ; - info[n].deadline = tain_infinite ; - info[n].parsefunc = &s6dns_message_parse_answer_mx ; - info[n].data = &mx ; - } + Also, fuck DNS. + */ - if (!s6dns_resolven_parse_g(info, n + !!mxpos, 0)) - qmailr_tempsys("Unable to perform DNS resolutions") ; +void dns_stuff (char const *host, char const *const *eaddr, unsigned int n, size_t *eaddrpos, genalloc *mxipind, stralloc *storage, unsigned int timeoutdns, char const *ipme4, unsigned int n4, char const *ipme6, unsigned int n6, uint32_t flags) +{ + skadns_t a = SKADNS_ZERO ; + genalloc mxipi = GENALLOC_ZERO ; /* mxipinfo */ + tain deadline ; + unsigned int pending = 0 ; + uint16_t mxn = 0 ; + uint16_t mxid = UINT16_MAX ; + cnameinfo cnames[n] ; + + tain_addsec_g(&deadline, timeoutdns) ; + if (!skadns_startf_g(&a, &deadline)) + qmailr_tempsys("Unable to start asynchronous DNS helper") ; for (unsigned int i = 0 ; i < n ; i++) { - recippos[i] = storage->len ; - // TODO: box_encode(recip[i], atpos[i], storage) ; - if (!stralloc_catb(storage, "@", 1)) dienomem() ; - if (!info[i].status && genalloc_len(s6dns_domain_t, &cnames[i].ds)) + char const *at = strrchr(eaddr[i], '@') ; + cnames[i].sa = stralloc_zero ; + if (at) { - if (!s6dns_domain_decode(genalloc_s(s6dns_domain_t, &cnames[i].ds))) - qmailr_tempsys("Unable to parse CNAME") ; - if (!stralloc_readyplus(storage, 256)) dienomem() ; - recippos[i] = storage->len ; - storage->len += s6dns_domain_tostring(storage->s + storage->len, 255, genalloc_s(s6dns_domain_t, &cnames[i].ds)) ; - if (storage->s[storage->len-1] == '.') --storage->len ; - storage->s[storage->len++] = 0 ; + s6dns_domain_t q ; + size_t len = strlen(at+1) ; + cnames[i].atpos = at - eaddr[i] ; + if (!stralloc_catb(&cnames[i].sa, at+1, len)) dienomem() ; + if (!s6dns_domain_fromstring_noqualify_encode(&q, at+1, len)) + qmailr_tempsys("Unable to DNS-encode recipient domain") ; + if (!skadns_send_g(&a, &cnames[i].id, &q, S6DNS_T_CNAME, &deadline, &deadline)) + qmailr_tempsys("Unable to send CNAME DNS query") ; + cnames[i].count = 1 ; + pending++ ; + } + else + { + cnames[i].id = UINT16_MAX ; + cnames[i].count = 0 ; + cnames[i].atpos = strlen(eaddr[i]) ; } - else if (!stralloc_cats(storage, recip[i] + atpos[i] + 1)) dienomem() ; - if (!stralloc_0(storage)) dienomem() ; } - if (mxpos && !info[n].status && genalloc_len(s6dns_message_rr_mx_t, &mx)) + if (flags & 1) { - s6dns_message_rr_mx_t *mxs = genalloc_s(s6dns_message_rr_mx_t, &mx) ; - size_t mxlen = genalloc_len(s6dns_message_rr_mx_t, &mx) ; - qsort(mxs, mxlen, sizeof(s6dns_message_rr_mx_t), &mx_cmp) ; - if (!genalloc_readyplus(size_t, mxpos, mxlen)) dienomem() ; - for (size_t i = 0 ; i < mxlen ; i++) - { - if (!s6dns_domain_decode(&mxs[i].exchange)) qmailr_tempsys("Unable to parse MX record") ; - if (!stralloc_readyplus(storage, 256)) dienomem() ; - genalloc_catb(size_t, mxpos, storage->len, 1) ; - storage->len += s6dns_domain_tostring(storage->s + storage->len, 255, &mxs[i].exchange) ; - storage->s[storage->len++] = 0 ; - } - genalloc_free(s6dns_message_rr_mx_t, &mx) ; + s6dns_domain_t q ; + if (!s6dns_domain_fromstring_noqualify_encode(&q, host, strlen(host))) + qmailr_tempsys("Unable to DNS-encode host domain") ; + if (!skadns_send_g(&a, &mxid, &q, S6DNS_T_MX, &deadline, &deadline)) + qmailr_tempsys("Unable to send MX DNS query") ; + pending++ ; + } + else + { + mxn = 1 ; + pending += use_host_as_mx(&a, host, &mxipi, &deadline) ; } -} -void dns_ip_of_mx (size_t const *pos, unsigned int n, mxip *tab, stralloc *storage, char const *ipme4, unsigned int n4, char const *ipme6, unsigned int n6) -{ -#ifdef SKALIBS_IPV6_ENABLED - unsigned int const N = n << 1 ; - stralloc ip6[n] ; -#else - unsigned int const N = n ; -#endif - stralloc ip4[n] ; - s6dns_resolve_t info[N] ; - for (unsigned int i = 0 ; i < n ; i++) + while (pending) { - if (!s6dns_domain_fromstring_noqualify_encode(&info[i].q, storage->s + pos[i], strlen(storage->s + pos[i]))) - qmailr_tempsys("Unable to DNS-encode MX") ; - ip4[i] = stralloc_zero ; - info[i].qtype = S6DNS_T_A ; - info[i].options = S6DNS_O_RECURSIVE ; - info[i].deadline = tain_infinite ; - info[i].parsefunc = &s6dns_message_parse_answer_a ; - info[i].data = ip4 + i ; + uint16_t *ids ; + iopause_fd x = { .fd = skadns_fd(&a), .events = IOPAUSE_READ } ; + int r = iopause_g(&x, 1, &deadline) ; + if (r == -1) qmailr_tempsys("Unable to iopause") ; + if (!r) qmailr_tempsys("Timed out waiting for DNS") ; + r = skadns_update(&a) ; + if (r == -1) qmailr_tempsys("Unable to read DNS answers") ; + ids = genalloc_s(uint16_t, &a.list) ; + for (size_t j = 0 ; j < genalloc_len(uint16_t, &a.list) ; j++) + { + char const *packet = skadns_packet(&a, ids[j]) ; + uint16_t packetlen = skadns_packetlen(&a, ids[j]) ; + if (!packet) qmailr_tempsys("DNS packet reading error") ; + if (ids[j] == mxid) /* return from MX query */ + { + s6dns_message_header_t h ; + genalloc mxes = GENALLOC_ZERO ; /* s6dns_message_rr_mx_t */ + r = s6dns_message_parse(&h, packet, packetlen, &s6dns_message_parse_answer_mx, &mxes) ; + if (r == -1) qmailr_tempsys("DNS packet parsing error") ; + if (!r) + { + if (errno == EBUSY || errno == EIO) qmailr_temp("Temporary DNS error while resolving MX") ; + else qmailr_perm("DNS CNAME resolution error") ; + } + skadns_release(&a, ids[j]) ; + pending-- ; + mxid = UINT16_MAX ; + if (r >= 2) /* we have MXes, ask for their IPs */ + { + s6dns_message_rr_mx_t *mxs = genalloc_s(s6dns_message_rr_mx_t, &mxes) ; + mxn = genalloc_len(s6dns_message_rr_mx_t, &mxes) ; + if (!genalloc_readyplus(mxipinfo, &mxipi, mxn)) dienomem() ; + qsort(mxs, mxn, sizeof(s6dns_message_rr_mx_t), &mx_cmp) ; + for (unsigned int i = 0 ; i < mxn ; i++) + { + mxipinfo *p = genalloc_s(mxipinfo, &mxipi) + i ; + p->ip4 = p->ip6 = stralloc_zero ; + if (!skadns_send_g(&a, &p->id4, &mxs[i].exchange, S6DNS_T_A, &deadline, &deadline)) + qmailr_tempsys("Unable to send A DNS query") ; + pending++ ; #ifdef SKALIBS_IPV6_ENABLED - ip6[i] = stralloc_zero ; - info[n+i].q = info[i].q ; - info[n+i].qtype = S6DNS_T_A ; - info[n+i].options = S6DNS_O_RECURSIVE ; - info[n+i].deadline = tain_infinite ; - info[n+i].parsefunc = &s6dns_message_parse_answer_aaaa ; - info[n+i].data = ip6 + i ; + if (!skadns_send_g(&a, &p->id6, &mxs[i].exchange, S6DNS_T_AAAA, &deadline, &deadline)) + qmailr_tempsys("Unable to send AAAA DNS query") ; + pending++ ; #endif - } - - if (!s6dns_resolven_parse_g(info, N, 0)) - qmailr_tempsys("Unable to perform DNS resolutions") ; + } + genalloc_free(s6dns_message_rr_mx_t, &mxes) ; + } + else + { + mxn = 1 ; + pending += use_host_as_mx(&a, host, &mxipi, &deadline) ; + } + continue ; + } - for (unsigned int i = 0 ; i < n ; i++) - { - if (!info[i].status) - { - for (unsigned int j = 0 ; j < ip4[i].len ; j += 4) + for (unsigned int i = 0 ; i < n ; i++) if (ids[j] == cnames[i].id) /* return from CNAME query */ { - if (bsearch(ip4[i].s + j, ipme4, n4, 4, &qmailr_memcmp4)) + s6dns_message_header_t h ; + s6dns_dpag_t dlist = { .ds = GENALLOC_ZERO, .rtype = S6DNS_T_CNAME } ; + r = s6dns_message_parse(&h, packet, packetlen, &s6dns_message_parse_answer_domain, &dlist) ; + if (r == -1) qmailr_tempsys("DNS packet parsing error") ; + if (!r) + { + if (errno == EBUSY || errno == EIO) qmailr_temp("Temporary DNS error while resolving CNAME") ; + else qmailr_perm("DNS CNAME resolution error") ; + } + skadns_release(&a, ids[j]) ; + pending-- ; + if (r >= 2) /* it's a CNAME, loop on it */ { - memmove(ip4[i].s + j, ip4[i].s + ip4[i].len - 4, 4) ; - ip4[i].len -= 4 ; + s6dns_domain_t *domain = genalloc_s(s6dns_domain_t, &dlist.ds) ; + if (cnames[i].count++ >= 100) qmailr_temp("DNS CNAME loop") ; + if (!skadns_send_g(&a, &cnames[i].id, domain, S6DNS_T_CNAME, &deadline, &deadline)) + qmailr_tempsys("Unable to send CNAME DNS query") ; + pending++ ; + if (!stralloc_ready(&cnames[i].sa, 256)) dienomem() ; + s6dns_domain_decode(domain) ; + cnames[i].sa.len = s6dns_domain_tostring(cnames[i].sa.s, 256, domain) ; + genalloc_free(s6dns_domain_t, &dlist.ds) ; } + else cnames[i].id = UINT16_MAX ; /* that's the canonical host in cnames[i].sa */ + continue ; } - random_unsort(ip4[i].s, ip4[i].len >> 2, 4) ; - tab[i].pos4 = storage->len ; - tab[i].n4 = ip4[i].len >> 2 ; - if (!stralloc_catb(storage, ip4[i].s, ip4[i].len)) dienomem() ; - stralloc_free(ip4 + i) ; - } -#ifdef SKALIBS_IPV6_ENABLED - if (!info[n+i].status) - { - for (unsigned int j = 0 ; j < ip6[i].len ; j += 16) + for (unsigned int i = 0 ; i < mxn ; i++) { - if (bsearch(ip6[i].s + j, ipme6, n6, 16, &qmailr_memcmp16)) + mxipinfo *p = genalloc_s(mxipinfo, &mxipi) + i ; + if (ids[j] == p->id4) + { + s6dns_message_header_t h ; + r = s6dns_message_parse(&h, packet, packetlen, &s6dns_message_parse_answer_a, &p->ip4) ; + if (r == -1) qmailr_tempsys("DNS packet parsing error") ; + if (!r) + { + if (errno == EBUSY || errno == EIO) qmailr_temp("Temporary DNS error while resolving A") ; + else qmailr_perm("DNS A resolution error") ; + } + skadns_release(&a, ids[j]) ; + pending-- ; + p->id4 = UINT16_MAX ; + for (unsigned int k = 0 ; k < p->ip4.len ; k += 4) + { + if (bsearch(p->ip4.s + k, ipme4, n4, 4, &qmailr_memcmp4)) + { + memmove(p->ip4.s + k, p->ip4.s + p->ip4.len - 4, 4) ; + p->ip4.len -= 4 ; + k -= 4 ; + } + } + } +#ifdef SKALIBS_IPV6_ENABLED + else if (ids[j] == p->id6) { - memmove(ip6[i].s + j, ip6[i].s + ip6[i].len - 16, 16) ; - ip6[i].len -= 16 ; + s6dns_message_header_t h ; + r = s6dns_message_parse(&h, packet, packetlen, &s6dns_message_parse_answer_aaaa, &p->ip6) ; + if (r == -1) qmailr_tempsys("DNS packet parsing error") ; + if (!r) + { + if (errno == EBUSY || errno == EIO) qmailr_temp("Temporary DNS error while resolving AAAA") ; + else qmailr_perm("DNS AAAA resolution error") ; + } + skadns_release(&a, ids[j]) ; + pending-- ; + p->id6 = UINT16_MAX ; + for (unsigned int k = 0 ; k < p->ip6.len ; k += 16) + { + if (bsearch(p->ip6.s + k, ipme6, n6, 16, &qmailr_memcmp16)) + { + memmove(p->ip6.s + k, p->ip6.s + p->ip6.len - 16, 16) ; + p->ip6.len -= 16 ; + k -= 16 ; + } + } } +#endif } - random_unsort(ip6[i].s, ip6[i].len >> 4, 16) ; - tab[i].pos6 = storage->len ; - tab[i].n6 = ip6[i].len >> 4 ; - if (!stralloc_catb(storage, ip6[i].s, ip6[i].len)) dienomem() ; - stralloc_free(ip6 + i) ; } -#endif + } + skadns_end(&a) ; /* we done buddy */ + for (unsigned int i = 0 ; i < n ; i++) + { + eaddrpos[i] = storage->len ; + if (!qmailr_box_encode(eaddr[i], cnames[i].atpos, storage)) dienomem() ; + if (cnames[i].count) + { + if (!stralloc_catb(storage, "@", 1)) dienomem() ; + if (!stralloc_catb(storage, cnames[i].sa.s, cnames[i].sa.len)) dienomem() ; + stralloc_free(&cnames[i].sa) ; + } + if (!stralloc_0(storage)) dienomem() ; + } + + if (!genalloc_readyplus(mxip, mxipind, mxn)) dienomem() ; + for (unsigned int i = 0 ; i < mxn ; i++) + { + mxip data ; + mxipinfo *p = genalloc_s(mxipinfo, &mxipi) + i ; + data.n4 = p->ip4.len >> 2 ; + data.pos4 = storage->len ; + if (!stralloc_catb(storage, p->ip4.s, p->ip4.len)) dienomem() ; + stralloc_free(&p->ip4) ; +#ifdef SKALIBS_IPV6_ENABLED + data.n6 = p->ip6.len >> 4 ; + data.pos6 = storage->len ; + if (!stralloc_catb(storage, p->ip6.s, p->ip6.len)) dienomem() ; + stralloc_free(&p->ip6) ; + genalloc_catb(mxip, mxipind, &data, 1) ; +#endif } + genalloc_free(mxipinfo, &mxipi) ; } |