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         struct aibuf {
  20                 struct addrinfo ai;
  21                 union sa {
  22                         struct sockaddr_in sin;
  23                         struct sockaddr_in6 sin6;
  24                 } sa;
  25         } *out;
  26
  27         if (!host && !serv) return EAI_NONAME;
  28
  29         if (hint) {
  30                 family = hint->ai_family;
  31                 flags = hint->ai_flags;
  32                 proto = hint->ai_protocol;
  33                 socktype = hint->ai_socktype;
  34
  35                 const int mask = AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST |
  36                         AI_V4MAPPED | AI_ALL | AI_ADDRCONFIG | AI_NUMERICSERV;
  37                 if ((flags & mask) != flags)
  38                         return EAI_BADFLAGS;
  39
  40                 switch (family) {
  41                 case AF_INET:
  42                 case AF_INET6:
  43                 case AF_UNSPEC:
  44                         break;
  45                 default:
  46                         return EAI_FAMILY;
  47                 }
  48         }
  49
  50         if (flags & AI_ADDRCONFIG) {
  51                 /* Define the "an address is configured" condition for address
  52                  * families via ability to create a socket for the family plus
  53                  * routability of the loopback address for the family. */
  54                 static const struct sockaddr_in lo4 = {
  55                         .sin_family = AF_INET, .sin_port = 65535,
  56                         .sin_addr.s_addr = __BYTE_ORDER == __BIG_ENDIAN
  57                                 ? 0x7f000001 : 0x0100007f
  58                 };
  59                 static const struct sockaddr_in6 lo6 = {
  60                         .sin6_family = AF_INET6, .sin6_port = 65535,
  61                         .sin6_addr = IN6ADDR_LOOPBACK_INIT
  62                 };
  63                 int tf[2] = { AF_INET, AF_INET6 };
  64                 const void *ta[2] = { &lo4, &lo6 };
  65                 socklen_t tl[2] = { sizeof lo4, sizeof lo6 };
  66                 for (i=0; i<2; i++) {
  67                         if (family==tf[1-i]) continue;
  68                         int s = socket(tf[i], SOCK_CLOEXEC|SOCK_DGRAM,
  69                                 IPPROTO_UDP);
  70                         if (s>=0) {
  71                                 int cs;
  72                                 pthread_setcancelstate(
  73                                         PTHREAD_CANCEL_DISABLE, &cs);
  74                                 int r = connect(s, ta[i], tl[i]);
  75                                 pthread_setcancelstate(cs, 0);
  76                                 close(s);
  77                                 if (!r) continue;
  78                         }
  79                         switch (errno) {
  80                         case EADDRNOTAVAIL:
  81                         case EAFNOSUPPORT:
  82                         case EHOSTUNREACH:
  83                         case ENETDOWN:
  84                         case ENETUNREACH:
  85                                 break;
  86                         default:
  87                                 return EAI_SYSTEM;
  88                         }
  89                         if (family == tf[i]) return EAI_NONAME;
  90                         family = tf[1-i];
  91                 }
  92         }
  93
  94         nservs = __lookup_serv(ports, serv, proto, socktype, flags);
  95         if (nservs < 0) return nservs;
  96
  97         naddrs = __lookup_name(addrs, canon, host, family, flags);
  98         if (naddrs < 0) return naddrs;
  99
 100         nais = nservs * naddrs;
 101         canon_len = strlen(canon);
 102         out = calloc(1, nais * sizeof(*out) + canon_len + 1);
 103         if (!out) return EAI_MEMORY;
 104
 105         if (canon_len) {
 106                 outcanon = (void *)&out[nais];
 107                 memcpy(outcanon, canon, canon_len+1);
 108         } else {
 109                 outcanon = 0;
 110         }
 111
 112         for (k=i=0; i<naddrs; i++) for (j=0; j<nservs; j++, 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                         .ai_next = &out[k+1].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[nais-1].ai.ai_next = 0;
 138         *res = &out->ai;
 139         return 0;
 140 }