nameinfo.c

   1 /*
   2  * Copyright (C) 2012-2020 all contributors <cmogstored-public@yhbt.net>
   3  * License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
   4  */
   5 #include "cmogstored.h"
   6 #include <arpa/inet.h>
   7
   8 /*
   9  * small replacement for getnameinfo(3), this only handles numeric types
  10  * for IPv4 and IPv6 and uses the compact mog_ni structure to reduce
  11  * stack usage in error reporting.
  12  */
  13 void mog_nameinfo(struct mog_packaddr *mpa, struct mog_ni *ni)
  14 {
  15         char *hostptr = ni->ni_host;
  16         size_t hostlen = sizeof(ni->ni_host) - (sizeof("[]") - 1);
  17         char *servptr = ni->ni_serv + 1; /* offset for ':' */
  18         size_t servlen = sizeof(ni->ni_serv) - 1; /* offset for ':' */
  19         int rc;
  20         const void *src;
  21         const char *ret;
  22
  23         if (mpa->sa_family == AF_INET6) {
  24                 hostptr[0] = '['; /* leading '[' */
  25                 src = mpa->as.in6_ptr;
  26                 hostptr++;
  27         } else {
  28                 assert(mpa->sa_family == AF_INET && "bad family");
  29                 src = &mpa->as.in_addr;
  30         }
  31
  32         ret = inet_ntop(mpa->sa_family, src, hostptr, (socklen_t)hostlen);
  33
  34         /* terminate serv string on error */
  35         assert(ret == hostptr && "inet_ntop");
  36         ni->ni_serv[0] = ':';
  37
  38         /* add trailing ']' */
  39         if (mpa->sa_family == AF_INET6) {
  40                 hostlen = strlen(hostptr);
  41                 hostptr[hostlen] = ']';
  42                 hostptr[hostlen + 1] = 0;
  43         }
  44
  45         /* port number */
  46         rc = snprintf(servptr, servlen, "%u", (unsigned)ntohs(mpa->port));
  47         assert(rc > 0 && rc < (int)servlen && "we suck at snprintf");
  48 }