src/poll.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2009, 2010 Daniel Borkmann.
   5  * Subject to the GPL.
   6  */
   7
   8 #ifndef POLL_H
   9 #define POLL_H
  10
  11 #define _GNU_SOURCE
  12 #include <poll.h>
  13 #include <errno.h>
  14 #include <sys/poll.h>
  15 #include <sys/socket.h>
  16
  17 #include "die.h"
  18
  19 #ifndef POLLRDNORM
  20 # define POLLRDNORM 0x0040
  21 #endif
  22 #ifndef POLLWRNORM
  23 # define POLLWRNORM 0x0100
  24 #endif
  25 #ifndef POLLRDHUP
  26 # define POLLRDHUP  0x2000
  27 #endif
  28
  29 #define POLL_NEXT_PKT 0
  30 #define POLL_MOVE_OUT 1
  31
  32 static inline void prepare_polling(int sock, struct pollfd *pfd)
  33 {
  34         memset(pfd, 0, sizeof(*pfd));
  35
  36         pfd->fd = sock;
  37         pfd->revents = 0;
  38         pfd->events = POLLIN | POLLRDNORM | POLLERR;
  39 }
  40
  41 static inline int poll_error_maybe_die(int sock, struct pollfd *pfd)
  42 {
  43         if ((pfd->revents & (POLLHUP | POLLRDHUP | POLLERR | POLLNVAL)) == 0)
  44                 return POLL_NEXT_PKT;
  45
  46         if (pfd->revents & (POLLHUP | POLLRDHUP))
  47                 error_and_die(EXIT_FAILURE, "Hangup on socket occured!\n");
  48
  49         if (pfd->revents & POLLERR) {
  50                 int tmp;
  51
  52                 errno = 0;
  53                 /* recv is more specififc on the error */
  54                 if (recv(sock, &tmp, sizeof(tmp), MSG_PEEK) >= 0)
  55                         return POLL_NEXT_PKT;
  56
  57                 if (errno == ENETDOWN)
  58                         error_and_die(EXIT_FAILURE, "Interface went down!\n");
  59                 return POLL_MOVE_OUT;
  60         }
  61
  62         if (pfd->revents & POLLNVAL) {
  63                 whine("Invalid polling request on socket!\n");
  64                 return POLL_MOVE_OUT;
  65         }
  66
  67         return POLL_NEXT_PKT;
  68 }
  69
  70 #endif /* POLL_H */