diff options
| -rw-r--r-- | src/network/__dns.c | 282 | ||||
| -rw-r--r-- | src/network/dns_parse.c | 31 | ||||
| -rw-r--r-- | src/network/getnameinfo.c | 59 | ||||
| -rw-r--r-- | src/network/lookup_name.c | 82 |
4 files changed, 145 insertions, 309 deletions
diff --git a/src/network/__dns.c b/src/network/__dns.c deleted file mode 100644 index 97d8031c..00000000 --- a/src/network/__dns.c +++ /dev/null @@ -1,282 +0,0 @@ -#include <stdint.h> -#include <netdb.h> -#include <stdio.h> -#include <fcntl.h> -#include <limits.h> -#include <string.h> -#include <sys/socket.h> -#include <poll.h> -#include <netinet/in.h> -#include <time.h> -#include <ctype.h> -#include <unistd.h> -#include <pthread.h> -#include <errno.h> -#include "__dns.h" -#include "stdio_impl.h" - -#define TIMEOUT 5 -#define RETRY 1000 -#define PACKET_MAX 512 -#define PTR_MAX (64 + sizeof ".in-addr.arpa") - -static void cleanup(void *p) -{ - close((intptr_t)p); -} - -int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt) -{ - time_t t0 = time(0); - int fd; - FILE *f, _f; - unsigned char _buf[256]; - char line[64], *s, *z; - union { - struct sockaddr_in sin; - struct sockaddr_in6 sin6; - } sa = {0}, ns[3] = {{0}}; - socklen_t sl = sizeof sa.sin; - int nns = 0; - int family = AF_INET; - unsigned char q[280] = "", *r = dest; - int ql; - int rlen; - int got = 0, failed = 0; - int errcode = EAI_AGAIN; - int i, j; - struct timespec ts; - struct pollfd pfd; - int id; - int cs; - - pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); - - /* Construct query template - RR and ID will be filled later */ - if (strlen(name)-1 >= 254U) return EAI_NONAME; - q[2] = q[5] = 1; - strcpy((char *)q+13, name); - for (i=13; q[i]; i=j+1) { - for (j=i; q[j] && q[j] != '.'; j++); - if (j-i-1u > 62u) return EAI_NONAME; - q[i-1] = j-i; - } - q[i+3] = 1; - ql = i+4; - - /* Make a reasonably unpredictable id */ - clock_gettime(CLOCK_REALTIME, &ts); - id = ts.tv_nsec + ts.tv_nsec/65536UL & 0xffff; - - /* Get nameservers from resolv.conf, fallback to localhost */ - f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf); - if (f) for (nns=0; nns<3 && fgets(line, sizeof line, f); ) { - if (strncmp(line, "nameserver", 10) || !isspace(line[10])) - continue; - for (s=line+11; isspace(*s); s++); - for (z=s; *z && !isspace(*z); z++); - *z=0; - if (__ipparse(ns+nns, AF_UNSPEC, s) < 0) continue; - ns[nns].sin.sin_port = htons(53); - if (ns[nns++].sin.sin_family == AF_INET6) { - family = AF_INET6; - sl = sizeof sa.sin6; - } - } - if (f) __fclose_ca(f); - if (!nns) { - ns[0].sin.sin_family = family = AF_INET; - ns[0].sin.sin_port = htons(53); - ns[0].sin.sin_addr.s_addr = htonl(0x7f000001); - nns=1; - sl = sizeof sa.sin; - } - - /* Get local address and open/bind a socket */ - sa.sin.sin_family = family; - fd = socket(family, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); - - /* Handle case where system lacks IPv6 support */ - if (fd < 0 && errno == EAFNOSUPPORT) { - if (family != AF_INET6) return EAI_SYSTEM; - fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); - family = AF_INET; - } - if (fd < 0) return EAI_SYSTEM; - - /* Convert any IPv4 addresses in a mixed environment to v4-mapped */ - if (family == AF_INET6) { - setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){0}, sizeof 0); - for (i=0; i<nns; i++) { - if (ns[i].sin.sin_family != AF_INET) continue; - memcpy(ns[i].sin6.sin6_addr.s6_addr+12, - &ns[i].sin.sin_addr, 4); - memcpy(ns[i].sin6.sin6_addr.s6_addr, - "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12); - ns[i].sin6.sin6_family = AF_INET6; - ns[i].sin6.sin6_flowinfo = 0; - ns[i].sin6.sin6_scope_id = 0; - } - } - - pthread_cleanup_push(cleanup, (void *)(intptr_t)fd); - pthread_setcancelstate(cs, 0); - - if (bind(fd, (void *)&sa, sl) < 0) { - errcode = EAI_SYSTEM; - goto out; - } - - pfd.fd = fd; - pfd.events = POLLIN; - - /* Loop until we timeout; break early on success */ - for (; time(0)-t0 < TIMEOUT; ) { - - /* Query all configured namservers in parallel */ - for (i=0; i<rrcnt; i++) if (rr[i]) for (j=0; j<nns; j++) { - q[0] = id+i >> 8; - q[1] = id+i; - q[ql-3] = rr[i]; - sendto(fd, q, ql, MSG_NOSIGNAL, (void *)&ns[j], sl); - } - - /* Wait for a response, or until time to retry */ - if (poll(&pfd, 1, RETRY) <= 0) continue; - - /* Process any and all replies */ - while (got+failed < rrcnt && (rlen = recvfrom(fd, r, 512, 0, - (void *)&sa, (socklen_t[1]){sl})) >= 2) - { - /* Ignore replies from addresses we didn't send to */ - for (i=0; i<nns; i++) if (!memcmp(ns+i, &sa, sl)) break; - if (i==nns) continue; - - /* Compute index of the query from id */ - i = r[0]*256+r[1] - id & 0xffff; - if ((unsigned)i >= rrcnt || !rr[i]) continue; - - /* Interpret the result code */ - switch (r[3] & 15) { - case 0: - got++; - break; - case 3: - if (1) errcode = EAI_NONAME; else - default: - errcode = EAI_FAIL; - failed++; - } - - /* Mark this record as answered */ - rr[i] = 0; - r += 512; - } - - /* Check to see if we have answers to all queries */ - if (got+failed == rrcnt) break; - } -out: - pthread_cleanup_pop(1); - - /* Return the number of results, or an error code if none */ - if (got) return got; - return errcode; -} - -static void mkptr4(char *s, const unsigned char *ip) -{ - sprintf(s, "%d.%d.%d.%d.in-addr.arpa", - ip[3], ip[2], ip[1], ip[0]); -} - -static void mkptr6(char *s, const unsigned char *ip) -{ - static const char xdigits[] = "0123456789abcdef"; - int i; - for (i=15; i>=0; i--) { - *s++ = xdigits[ip[i]&15]; *s++ = '.'; - *s++ = xdigits[ip[i]>>4]; *s++ = '.'; - } - strcpy(s, "ip6.arpa"); -} - -int __dns_query(unsigned char *r, const void *a, int family, int ptr) -{ - char buf[PTR_MAX]; - int rr[2], rrcnt = 1; - - if (ptr) { - if (family == AF_INET6) mkptr6(buf, a); - else mkptr4(buf, a); - rr[0] = RR_PTR; - a = buf; - } else if (family == AF_INET6) { - rr[0] = RR_AAAA; - } else { - rr[0] = RR_A; - if (family != AF_INET) rr[rrcnt++] = RR_AAAA; - } - - return __dns_doqueries(r, a, rr, rrcnt); -} - -int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int); - -int __dns_get_rr(void *dest, size_t stride, size_t maxlen, size_t limit, const unsigned char *r, int rr, int dec) -{ - int qdcount, ancount; - const unsigned char *p; - char tmp[256]; - int found = 0; - int len; - - if ((r[3]&15)) return 0; - p = r+12; - qdcount = r[4]*256 + r[5]; - ancount = r[6]*256 + r[7]; - if (qdcount+ancount > 64) return -1; - while (qdcount--) { - while (p-r < 512 && *p-1U < 127) p++; - if (*p>193 || (*p==193 && p[1]>254) || p>r+506) - return -1; - p += 5 + !!*p; - } - while (ancount--) { - while (p-r < 512 && *p-1U < 127) p++; - if (*p>193 || (*p==193 && p[1]>254) || p>r+506) - return -1; - p += 1 + !!*p; - len = p[8]*256 + p[9]; - if (p+len > r+512) return -1; - if (p[1]==rr && len <= maxlen) { - if (dec && __dn_expand(r, r+512, p+10, tmp, sizeof tmp)<0) - return -1; - if (dest && limit) { - if (dec) strcpy(dest, tmp); - else memcpy(dest, p+10, len); - dest = (char *)dest + stride; - limit--; - } - found++; - } - p += 10 + len; - } - return found; -} - -int __dns_count_addrs(const unsigned char *r, int cnt) -{ - int found=0, res, i; - static const int p[2][2] = { { 4, RR_A }, { 16, RR_AAAA } }; - - while (cnt--) { - for (i=0; i<2; i++) { - res = __dns_get_rr(0, 0, p[i][0], -1, r, p[i][1], 0); - if (res < 0) return res; - found += res; - } - r += 512; - } - return found; -} diff --git a/src/network/dns_parse.c b/src/network/dns_parse.c new file mode 100644 index 00000000..aa0d39f3 --- /dev/null +++ b/src/network/dns_parse.c @@ -0,0 +1,31 @@ +#include <string.h> + +int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), void *ctx) +{ + int qdcount, ancount; + const unsigned char *p; + int len; + + if ((r[3]&15)) return 0; + p = r+12; + qdcount = r[4]*256 + r[5]; + ancount = r[6]*256 + r[7]; + if (qdcount+ancount > 64) return -1; + while (qdcount--) { + while (p-r < rlen && *p-1U < 127) p++; + if (*p>193 || (*p==193 && p[1]>254) || p>r+506) + return -1; + p += 5 + !!*p; + } + while (ancount--) { + while (p-r < rlen && *p-1U < 127) p++; + if (*p>193 || (*p==193 && p[1]>254) || p>r+506) + return -1; + p += 1 + !!*p; + len = p[8]*256 + p[9]; + if (p+len > r+rlen) return -1; + if (callback(ctx, p[1], p+10, len, r) < 0) return -1; + p += 10 + len; + } + return 0; +} diff --git a/src/network/getnameinfo.c b/src/network/getnameinfo.c index 33f89a38..dfcf6eda 100644 --- a/src/network/getnameinfo.c +++ b/src/network/getnameinfo.c @@ -5,15 +5,50 @@ #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> -#include "__dns.h" + +int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *); +int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int); +int __res_mkquery(int, const char *, int, int, const unsigned char *, int, const unsigned char*, unsigned char *, int); +int __res_send(const unsigned char *, int, unsigned char *, int); + +#define PTR_MAX (64 + sizeof ".in-addr.arpa") +#define RR_PTR 12 + +static void mkptr4(char *s, const unsigned char *ip) +{ + sprintf(s, "%d.%d.%d.%d.in-addr.arpa", + ip[3], ip[2], ip[1], ip[0]); +} + +static void mkptr6(char *s, const unsigned char *ip) +{ + static const char xdigits[] = "0123456789abcdef"; + int i; + for (i=15; i>=0; i--) { + *s++ = xdigits[ip[i]&15]; *s++ = '.'; + *s++ = xdigits[ip[i]>>4]; *s++ = '.'; + } + strcpy(s, "ip6.arpa"); +} + +static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet) +{ + char tmp[256]; + if (rr != RR_PTR) return 0; + if (__dn_expand(packet, (const unsigned char *)packet + 512, + data, tmp, sizeof tmp) > 0) + strcpy(c, tmp); + return 0; + +} int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl, char *restrict node, socklen_t nodelen, char *restrict serv, socklen_t servlen, int flags) { + char ptr[PTR_MAX]; char buf[256]; - unsigned char reply[512]; int af = sa->sa_family; unsigned char *a; @@ -21,20 +56,32 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl, case AF_INET: a = (void *)&((struct sockaddr_in *)sa)->sin_addr; if (sl != sizeof(struct sockaddr_in)) return EAI_FAMILY; + mkptr4(ptr, a); break; case AF_INET6: a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr; if (sl != sizeof(struct sockaddr_in6)) return EAI_FAMILY; + if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12)) + mkptr6(ptr, a); + else + mkptr4(ptr, a+12); break; default: return EAI_FAMILY; } if (node && nodelen) { - if ((flags & NI_NUMERICHOST) - || __dns_query(reply, a, af, 1) <= 0 - || __dns_get_rr(buf, 0, 256, 1, reply, RR_PTR, 1) <= 0) - { + buf[0] = 0; + if (!(flags & NI_NUMERICHOST)) { + unsigned char query[18+PTR_MAX], reply[512]; + int qlen = __res_mkquery(0, ptr, 1, RR_PTR, + 0, 0, 0, query, sizeof query); + int rlen = __res_send(query, qlen, reply, sizeof reply); + buf[0] = 0; + if (rlen > 0) + __dns_parse(reply, rlen, dns_parse_callback, buf); + } + if (!*buf) { if (flags & NI_NAMEREQD) return EAI_NONAME; inet_ntop(af, a, buf, sizeof buf); } diff --git a/src/network/lookup_name.c b/src/network/lookup_name.c index e1b583ee..83c0fc27 100644 --- a/src/network/lookup_name.c +++ b/src/network/lookup_name.c @@ -9,7 +9,6 @@ #include "lookup.h" #include "stdio_impl.h" #include "syscall.h" -#include "__dns.h" static int is_valid_hostname(const char *host) { @@ -86,30 +85,71 @@ static int name_from_hosts(struct address buf[static MAXADDRS], char canon[stati return cnt; } -static int name_from_dns(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family) +struct dpc_ctx { + struct address *addrs; + char *canon; + int cnt; +}; + +int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *); +int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int); +int __res_mkquery(int, const char *, int, int, const unsigned char *, int, const unsigned char*, unsigned char *, int); +int __res_msend(int, const unsigned char *const *, const int *, unsigned char *const *, int *, int); + +#define RR_A 1 +#define RR_CNAME 5 +#define RR_AAAA 28 + +static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet) { - unsigned char reply[1024] = { 0 }, *p = reply; char tmp[256]; - int i, cnt = 0; - - /* Perform one or more DNS queries for host */ - int result = __dns_query(reply, name, family, 0); - if (result < 0) return result; + struct dpc_ctx *ctx = c; + switch (rr) { + case RR_A: + if (len != 4) return -1; + ctx->addrs[ctx->cnt].family = AF_INET; + memcpy(ctx->addrs[ctx->cnt++].addr, data, 4); + break; + case RR_AAAA: + if (len != 16) return -1; + ctx->addrs[ctx->cnt].family = AF_INET6; + memcpy(ctx->addrs[ctx->cnt++].addr, data, 16); + break; + case RR_CNAME: + if (__dn_expand(packet, (const unsigned char *)packet + 512, + data, tmp, sizeof tmp) > 0 && is_valid_hostname(tmp)) + strcpy(ctx->canon, tmp); + break; + } + return 0; +} - for (i=0; i<result; i++) { - if (family != AF_INET6) { - int j = __dns_get_rr(&buf[cnt].addr, sizeof *buf, 4, MAXADDRS-cnt, p, RR_A, 0); - while (j--) buf[cnt++].family = AF_INET; - } - if (family != AF_INET) { - int j = __dns_get_rr(&buf[cnt].addr, sizeof *buf, 16, MAXADDRS-cnt, p, RR_AAAA, 0); - while (j--) buf[cnt++].family = AF_INET6; - } - p += 512; +static int name_from_dns(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family) +{ + unsigned char qbuf[2][280], abuf[2][512]; + const unsigned char *qp[2] = { qbuf[0], qbuf[1] }; + unsigned char *ap[2] = { abuf[0], abuf[1] }; + int qlens[2], alens[2]; + int i, nq = 0; + struct dpc_ctx ctx = { .addrs = buf, .canon = canon }; + + if (family != AF_INET6) { + qlens[nq] = __res_mkquery(0, name, 1, RR_A, 0, 0, 0, + qbuf[nq], sizeof *qbuf); + nq++; } - __dns_get_rr(tmp, 0, 256, 1, reply, RR_CNAME, 1); - if (is_valid_hostname(tmp)) strcpy(canon, tmp); - return cnt; + if (family != AF_INET) { + qlens[nq] = __res_mkquery(0, name, 1, RR_AAAA, 0, 0, 0, + qbuf[nq], sizeof *qbuf); + nq++; + } + + if (__res_msend(nq, qp, qlens, ap, alens, sizeof *abuf) < 0) return EAI_SYSTEM; + + for (i=0; i<nq; i++) + __dns_parse(abuf[i], alens[i], dns_parse_callback, &ctx); + + return ctx.cnt; } int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, int flags) |