text: /*
  Copyright (c) 2007, 2008 by Juliusz Chroboczek
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
  */
  
  #include <unistd.h>
  #include <stdio.h>
  #include <fcntl.h>
  #include <string.h>
  #include <sys/ioctl.h>
  #include <sys/types.h>
  #include <sys/uio.h>
  #include <sys/socket.h>
  #include <netinet/in.h>
  #include <netinet/in_systm.h>
  #include <netinet/ip.h>
  #include <arpa/inet.h>
  #include <errno.h>
  
  #include "babeld.h"
  #include "util.h"
  #include "net.h"
  
  int
  babel_socket(int port)
  {
      struct sockaddr_in6 sin6;
      int s, rc;
      int saved_errno;
      int one = 1, zero = 0;
      const int ds = 0xc0;        /* CS6 - Network Control */
  
      s = socket(PF_INET6, SOCK_DGRAM, 0);
      if(s < 0)
          return -1;
  
      rc = setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
      if(rc < 0)
          goto fail;
  
      rc = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
      if(rc < 0)
          goto fail;
  
      rc = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
                      &zero, sizeof(zero));
      if(rc < 0)
          goto fail;
  
      rc = setsockopt(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS,
                      &one, sizeof(one));
      if(rc < 0)
          goto fail;
  
      rc = setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
                      &one, sizeof(one));
      if(rc < 0)
          goto fail;
  
  #ifdef IPV6_TCLASS
      rc = setsockopt(s, IPPROTO_IPV6, IPV6_TCLASS, &ds, sizeof(ds));
  #else
      rc = -1;
      errno = ENOSYS;
  #endif
      if(rc < 0)
          perror("Couldn't set traffic class");
  
      rc = fcntl(s, F_GETFL, 0);
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_SETFL, (rc | O_NONBLOCK));
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_GETFD, 0);
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_SETFD, rc | FD_CLOEXEC);
      if(rc < 0)
          goto fail;
  
      memset(&sin6, 0, sizeof(sin6));
      sin6.sin6_family = AF_INET6;
      sin6.sin6_port = htons(port);
      rc = bind(s, (struct sockaddr*)&sin6, sizeof(sin6));
      if(rc < 0)
          goto fail;
  
      return s;
  
   fail:
      saved_errno = errno;
      close(s);
      errno = saved_errno;
      return -1;
  }
  
  int
  babel_recv(int s, void *buf, int buflen, struct sockaddr *sin, int slen)
  {
      struct iovec iovec;
      struct msghdr msg;
      int rc;
  
      memset(&msg, 0, sizeof(msg));
      iovec.iov_base = buf;
      iovec.iov_len = buflen;
      msg.msg_name = sin;
      msg.msg_namelen = slen;
      msg.msg_iov = &iovec;
      msg.msg_iovlen = 1;
  
      rc = recvmsg(s, &msg, 0);
      return rc;
  }
  
  int
  babel_send(int s,
             const void *buf1, int buflen1, const void *buf2, int buflen2,
             const struct sockaddr *sin, int slen)
  {
      struct iovec iovec[2];
      struct msghdr msg;
      int rc, count = 0;
  
      iovec[0].iov_base = (void*)buf1;
      iovec[0].iov_len = buflen1;
      iovec[1].iov_base = (void*)buf2;
      iovec[1].iov_len = buflen2;
      memset(&msg, 0, sizeof(msg));
      msg.msg_name = (struct sockaddr*)sin;
      msg.msg_namelen = slen;
      msg.msg_iov = iovec;
      msg.msg_iovlen = 2;
  
      /* The Linux kernel can apparently keep returning EAGAIN indefinitely. */
  
   again:
      rc = sendmsg(s, &msg, 0);
      if(rc < 0) {
          if(errno == EINTR) {
              count++;
              if(count < 100)
                  goto again;
          } else if(errno == EAGAIN) {
              int rc2;
              rc2 = wait_for_fd(1, s, 5);
              if(rc2 > 0) {
                  count++;
                  if(count < 100)
                      goto again;
              }
              errno = EAGAIN;
          }
      }
      return rc;
  }
  
  int
  tcp_server_socket(int port, int local)
  {
      struct sockaddr_in6 sin6;
      int s, rc, saved_errno;
      int one = 1;
  
      s = socket(PF_INET6, SOCK_STREAM, 0);
      if(s < 0)
          return -1;
  
      rc = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_GETFL, 0);
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_SETFL, (rc | O_NONBLOCK));
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_GETFD, 0);
      if(rc < 0)
          goto fail;
  
      rc = fcntl(s, F_SETFD, rc | FD_CLOEXEC);
      if(rc < 0)
          goto fail;
  
      memset(&sin6, 0, sizeof(sin6));
      sin6.sin6_family = AF_INET6;
      sin6.sin6_port = htons(port);
      if(local) {
          rc = inet_pton(AF_INET6, "::1", &sin6.sin6_addr);
          if(rc < 0)
              goto fail;
      }
      rc = bind(s, (struct sockaddr*)&sin6, sizeof(sin6));
      if(rc < 0)
          goto fail;
  
      rc = listen(s, 2);
      if(rc < 0)
          goto fail;
  
      return s;
  
   fail:
      saved_errno = errno;
      close(s);
      errno = saved_errno;
      return -1;
  }
  