src/network/getaddrinfo.c

   1 #include <stdlib.h>
   2 #include <sys/socket.h>
   3 #include <netinet/in.h>
   4 #include <netdb.h>
   5 #include <string.h>
   6 #include <pthread.h>
   7 #include <unistd.h>
   8 #include <endian.h>
   9 #include <errno.h>
  10 #include "lookup.h"
  11
  12 int getaddrinfo(const char *restrict host, const char *restrict serv, const struct addrinfo *restrict hint, struct addrinfo **restrict res)
  13 {
  14         struct service ports[MAXSERVS];
  15         struct address addrs[MAXADDRS];
  16         char canon[256], *outcanon;
  17         int nservs, naddrs, nais, canon_len, i, j, k;
  18         int family = AF_UNSPEC, flags = 0, proto = 0, socktype = 0;
  19         int no_family = 0;
  20         struct aibuf *out;
  21
  22         if (!host && !serv) return EAI_NONAME;
  23
  24         if (hint) {
  25                 family = hint->ai_family;
  26                 flags = hint->ai_flags;
  27                 proto = hint->ai_protocol;
  28                 socktype = hint->ai_socktype;
  29
  30                 const int mask = AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST |
  31                         AI_V4MAPPED | AI_ALL | AI_ADDRCONFIG | AI_NUMERICSERV;
  32                 if ((flags & mask) != flags)
  33                         return EAI_BADFLAGS;
  34
  35                 switch (family) {
  36                 case AF_INET:
  37                 case AF_INET6:
  38                 case AF_UNSPEC:
  39                         break;
  40                 default:
  41                         return EAI_FAMILY;
  42                 }
  43         }
  44
  45         if (flags & AI_ADDRCONFIG) {
  46                 /* Define the "an address is configured" condition for address
  47                  * families via ability to create a socket for the family plus
  48                  * routability of the loopback address for the family. */
  49                 static const struct sockaddr_in lo4 = {
  50                         .sin_family = AF_INET, .sin_port = 65535,
  51                         .sin_addr.s_addr = __BYTE_ORDER == __BIG_ENDIAN
  52                                 ? 0x7f000001 : 0x0100007f
  53                 };
  54                 static const struct sockaddr_in6 lo6 = {
  55                         .sin6_family = AF_INET6, .sin6_port = 65535,
  56                         .sin6_addr = IN6ADDR_LOOPBACK_INIT
  57                 };
  58                 int tf[2] = { AF_INET, AF_INET6 };
  59                 const void *ta[2] = { &lo4, &lo6 };
  60                 socklen_t tl[2] = { sizeof lo4, sizeof lo6 };
  61                 for (i=0; i<2; i++) {
  62                         if (family==tf[1-i]) continue;
  63                         int s = socket(tf[i], SOCK_CLOEXEC|SOCK_DGRAM,
  64                                 IPPROTO_UDP);
  65                         if (s>=0) {
  66                                 int cs;
  67                                 pthread_setcancelstate(
  68                                         PTHREAD_CANCEL_DISABLE, &cs);
  69                                 int r = connect(s, ta[i], tl[i]);
  70                                 int saved_errno = errno;
  71                                 pthread_setcancelstate(cs, 0);
  72                                 close(s);
  73                                 if (!r) continue;
  74                                 errno = saved_errno;
  75                         }
  76                         switch (errno) {
  77                         case EADDRNOTAVAIL:
  78                         case EAFNOSUPPORT:
  79                         case EHOSTUNREACH:
  80                         case ENETDOWN:
  81                         case ENETUNREACH:
  82                                 break;
  83                         default:
  84                                 return EAI_SYSTEM;
  85                         }
  86                         if (family == tf[i]) no_family = 1;
  87                         family = tf[1-i];
  88                 }
  89         }
  90
  91         nservs = __lookup_serv(ports, serv, proto, socktype, flags);
  92         if (nservs < 0) return nservs;
  93
  94         naddrs = __lookup_name(addrs, canon, host, family, flags);
  95         if (naddrs < 0) return naddrs;
  96
  97         if (no_family) return EAI_NODATA;
  98
  99         nais = nservs * naddrs;
 100         canon_len = strlen(canon);
 101         out = calloc(1, nais * sizeof(*out) + canon_len + 1);
 102         if (!out) return EAI_MEMORY;
 103
 104         if (canon_len) {
 105                 outcanon = (void *)&out[nais];
 106                 memcpy(outcanon, canon, canon_len+1);
 107         } else {
 108                 outcanon = 0;
 109         }
 110
 111         for (k=i=0; i<naddrs; i++) for (j=0; j<nservs; j++, k++) {
 112                 out[k].slot = k;
 113                 out[k].ai = (struct addrinfo){
 114                         .ai_family = addrs[i].family,
 115                         .ai_socktype = ports[j].socktype,
 116                         .ai_protocol = ports[j].proto,
 117                         .ai_addrlen = addrs[i].family == AF_INET
 118                                 ? sizeof(struct sockaddr_in)
 119                                 : sizeof(struct sockaddr_in6),
 120                         .ai_addr = (void *)&out[k].sa,
 121                         .ai_canonname = outcanon };
 122                 if (k) out[k-1].ai.ai_next = &out[k].ai;
 123                 switch (addrs[i].family) {
 124                 case AF_INET:
 125                         out[k].sa.sin.sin_family = AF_INET;
 126                         out[k].sa.sin.sin_port = htons(ports[j].port);
 127                         memcpy(&out[k].sa.sin.sin_addr, &addrs[i].addr, 4);
 128                         break;
 129                 case AF_INET6:
 130                         out[k].sa.sin6.sin6_family = AF_INET6;
 131                         out[k].sa.sin6.sin6_port = htons(ports[j].port);
 132                         out[k].sa.sin6.sin6_scope_id = addrs[i].scopeid;
 133                         memcpy(&out[k].sa.sin6.sin6_addr, &addrs[i].addr, 16);
 134                         break;
 135                 }
 136         }
 137         out[0].ref = nais;
 138         *res = &out->ai;
 139         return 0;
 140 }