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, version 2.
   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 #define POLL_NEXT_PKT   0
  29 #define POLL_MOVE_OUT   1
  30
  31 static inline void prepare_polling(int sock, struct pollfd *pfd)
  32 {
  33         memset(pfd, 0, sizeof(*pfd));
  34         pfd->fd = sock;
  35         pfd->revents = 0;
  36         pfd->events = POLLIN | POLLRDNORM | POLLERR;
  37 }
  38
  39 static inline int poll_error_maybe_die(int sock, struct pollfd *pfd)
  40 {
  41         if ((pfd->revents & (POLLHUP | POLLRDHUP | POLLERR | POLLNVAL)) == 0)
  42                 return POLL_NEXT_PKT;
  43         if (pfd->revents & (POLLHUP | POLLRDHUP))
  44                 panic("Hangup on socket occured!\n");
  45         if (pfd->revents & POLLERR) {
  46                 int tmp;
  47                 errno = 0;
  48                 /* recv is more specififc on the error */
  49                 if (recv(sock, &tmp, sizeof(tmp), MSG_PEEK) >= 0)
  50                         return POLL_NEXT_PKT;
  51                 if (errno == ENETDOWN)
  52                         panic("Interface went down!\n");
  53                 return POLL_MOVE_OUT;
  54         }
  55         if (pfd->revents & POLLNVAL) {
  56                 whine("Invalid polling request on socket!\n");
  57                 return POLL_MOVE_OUT;
  58         }
  59         return POLL_NEXT_PKT;
  60 }
  61
  62 #endif /* POLL_H */