fusl/src/network/getaddrinfo.c

#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <string.h>
#include "lookup.h"

int getaddrinfo(const char* restrict host,
                const char* restrict serv,
                const struct addrinfo* restrict hint,
                struct addrinfo** restrict res) {
  struct service ports[MAXSERVS];
  struct address addrs[MAXADDRS];
  char canon[256], *outcanon;
  int nservs, naddrs, nais, canon_len, i, j, k;
  int family = AF_UNSPEC, flags = 0, proto = 0, socktype = 0;
  struct aibuf {
    struct addrinfo ai;
    union sa {
      struct sockaddr_in sin;
      struct sockaddr_in6 sin6;
    } sa;
  } * out;

  if (!host && !serv)
    return EAI_NONAME;

  if (hint) {
    family = hint->ai_family;
    flags = hint->ai_flags;
    proto = hint->ai_protocol;
    socktype = hint->ai_socktype;

    const int mask = AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST | AI_V4MAPPED |
                     AI_ALL | AI_ADDRCONFIG | AI_NUMERICSERV;
    if ((flags & mask) != flags)
      return EAI_BADFLAGS;

    switch (family) {
      case AF_INET:
      case AF_INET6:
      case AF_UNSPEC:
        break;
      default:
        return EAI_FAMILY;
    }
  }

  nservs = __lookup_serv(ports, serv, proto, socktype, flags);
  if (nservs < 0)
    return nservs;

  naddrs = __lookup_name(addrs, canon, host, family, flags);
  if (naddrs < 0)
    return naddrs;

  nais = nservs * naddrs;
  canon_len = strlen(canon);
  out = calloc(1, nais * sizeof(*out) + canon_len + 1);
  if (!out)
    return EAI_MEMORY;

  if (canon_len) {
    outcanon = (void*)&out[nais];
    memcpy(outcanon, canon, canon_len + 1);
  } else {
    outcanon = 0;
  }

  for (k = i = 0; i < naddrs; i++)
    for (j = 0; j < nservs; j++, k++) {
      out[k].ai =
          (struct addrinfo){.ai_family = addrs[i].family,
                            .ai_socktype = ports[j].socktype,
                            .ai_protocol = ports[j].proto,
                            .ai_addrlen = addrs[i].family == AF_INET
                                              ? sizeof(struct sockaddr_in)
                                              : sizeof(struct sockaddr_in6),
                            .ai_addr = (void*)&out[k].sa,
                            .ai_canonname = outcanon,
                            .ai_next = &out[k + 1].ai};
      switch (addrs[i].family) {
        case AF_INET:
          out[k].sa.sin.sin_family = AF_INET;
          out[k].sa.sin.sin_port = htons(ports[j].port);
          memcpy(&out[k].sa.sin.sin_addr, &addrs[i].addr, 4);
          break;
        case AF_INET6:
          out[k].sa.sin6.sin6_family = AF_INET6;
          out[k].sa.sin6.sin6_port = htons(ports[j].port);
          out[k].sa.sin6.sin6_scope_id = addrs[i].scopeid;
          memcpy(&out[k].sa.sin6.sin6_addr, &addrs[i].addr, 16);
          break;
      }
    }
  out[nais - 1].ai.ai_next = 0;
  *res = &out->ai;
  return 0;
}