libcody/netserver.cc

   1 // CODYlib              -*- mode:c++ -*-
   2 // Copyright (C) 2020 Nathan Sidwell, nathan@acm.org
   3 // License: Apache v2.0
   4
   5 // Cody
   6 #include "internal.hh"
   7 #if CODY_NETWORKING
   8 // C
   9 #include <cerrno>
  10 #include <cstring>
  11 // OS
  12 #include <netdb.h>
  13 #include <unistd.h>
  14 #include <arpa/inet.h>
  15 #include <netinet/in.h>
  16 #include <sys/un.h>
  17
  18 #ifndef AI_NUMERICSERV
  19 #define AI_NUMERICSERV 0
  20 #endif
  21
  22 // Server-side networking helpers
  23
  24 namespace Cody {
  25
  26 int ListenSocket (char const **e, sockaddr const *addr, socklen_t len,
  27                   unsigned backlog)
  28 {
  29   char const *errstr = nullptr;
  30
  31   int fd = socket (addr->sa_family, SOCK_STREAM, 0);
  32   if (fd < 0)
  33     {
  34       errstr = "creating socket";
  35
  36     fail:;
  37       int err = errno;
  38       if (e)
  39         *e = errstr;
  40       if (fd >= 0)
  41         close (fd);
  42       errno = err;
  43       return -1;
  44     }
  45
  46   if (bind (fd, addr, len) < 0)
  47     {
  48       errstr = "binding socket";
  49       goto fail;
  50     }
  51
  52   if (listen (fd, backlog ? backlog : 17) < 0)
  53     {
  54       errstr = "listening socket";
  55       goto fail;
  56     }
  57
  58   return fd;
  59 }
  60
  61 int ListenLocal (char const **e, char const *name, unsigned backlog)
  62 {
  63   sockaddr_un addr;
  64   size_t len = strlen (name);
  65
  66   if (len >= sizeof (addr.sun_path))
  67     {
  68       errno = ENAMETOOLONG;
  69       return -1;
  70     }
  71
  72   memset (&addr, 0, offsetof (sockaddr_un, sun_path));
  73   addr.sun_family = AF_UNIX;
  74   memcpy (addr.sun_path, name, len + 1);
  75
  76   return ListenSocket (e, (sockaddr *)&addr, sizeof (addr), backlog);
  77 }
  78
  79 int ListenInet6 (char const **e, char const *name, int port, unsigned backlog)
  80 {
  81   addrinfo *addrs = nullptr;
  82   int fd = -1;
  83   char const *errstr = nullptr;
  84
  85   fd = socket (AF_INET6, SOCK_STREAM, 0);
  86   if (fd < 0)
  87     {
  88       errstr = "creating socket";
  89
  90     fail:;
  91       int err = errno;
  92       if (e)
  93         *e = errstr;
  94       if (fd >= 0)
  95         close (fd);
  96       if (addrs)
  97         freeaddrinfo (addrs);
  98       errno = err;
  99       return -1;
 100     }
 101
 102   addrinfo hints;
 103   hints.ai_flags = AI_NUMERICSERV;
 104   hints.ai_family = AF_INET6;
 105   hints.ai_socktype = SOCK_STREAM;
 106   hints.ai_protocol = 0;
 107   hints.ai_addrlen = 0;
 108   hints.ai_addr = nullptr;
 109   hints.ai_canonname = nullptr;
 110   hints.ai_next = nullptr;
 111
 112   /* getaddrinfo requires a port number, but is quite happy to accept
 113      invalid ones.  So don't rely on it.  */
 114   if (int err = getaddrinfo (name, "0", &hints, &addrs))
 115     {
 116       errstr = gai_strerror (err);
 117       // What's the best errno to set?
 118       errno = 0;
 119       goto fail;
 120     }
 121
 122   sockaddr_in6 addr;
 123   memset (&addr, 0, sizeof (addr));
 124   addr.sin6_family = AF_INET6;
 125
 126   for (struct addrinfo *next = addrs; next; next = next->ai_next)
 127     if (next->ai_family == AF_INET6
 128         && next->ai_socktype == SOCK_STREAM)
 129       {
 130         sockaddr_in6 *in6 = (sockaddr_in6 *)next->ai_addr;
 131         in6->sin6_port = htons (port);
 132         if (ntohs (in6->sin6_port) != port)
 133           errno = EINVAL;
 134         else if (!bind (fd, next->ai_addr, next->ai_addrlen))
 135           goto listen;
 136       }
 137
 138   errstr = "binding socket";
 139   goto fail;
 140
 141  listen:;
 142   freeaddrinfo (addrs);
 143
 144   if (listen (fd, backlog ? backlog : 17) < 0)
 145     {
 146       errstr = "listening socket";
 147       goto fail;
 148     }
 149
 150   return fd;
 151 }
 152
 153 }
 154 #endif