pcap_rw.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2009 - 2013 Daniel Borkmann.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdint.h>
  10 #include <stdbool.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <errno.h>
  14
  15 #include "pcap.h"
  16 #include "built_in.h"
  17 #include "xutils.h"
  18 #include "xio.h"
  19 #include "die.h"
  20
  21 static ssize_t pcap_rw_write(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
  22                              const uint8_t *packet, size_t len)
  23 {
  24         ssize_t ret, hdrsize = pcap_get_hdr_length(phdr, type), hdrlen = 0;
  25
  26         ret = write_or_die(fd, &phdr->raw, hdrsize);
  27         if (unlikely(ret != hdrsize))
  28                 panic("Failed to write pkt header!\n");
  29
  30         hdrlen = pcap_get_length(phdr, type);
  31         if (unlikely(hdrlen != len))
  32                 return -EINVAL;
  33
  34         ret = write_or_die(fd, packet, hdrlen);
  35         if (unlikely(ret != hdrlen))
  36                 panic("Failed to write pkt payload!\n");
  37
  38         return hdrsize + hdrlen;
  39 }
  40
  41 static ssize_t pcap_rw_read(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
  42                             uint8_t *packet, size_t len)
  43 {
  44         ssize_t ret, hdrsize = pcap_get_hdr_length(phdr, type), hdrlen = 0;
  45
  46         ret = read_or_die(fd, &phdr->raw, hdrsize);
  47         if (unlikely(ret != hdrsize))
  48                 return -EIO;
  49
  50         hdrlen = pcap_get_length(phdr, type);
  51         if (unlikely(hdrlen == 0 || hdrlen > len))
  52                 return -EINVAL;
  53
  54         ret = read(fd, packet, hdrlen);
  55         if (unlikely(ret != hdrlen))
  56                 return -EIO;
  57
  58         return hdrsize + hdrlen;
  59 }
  60
  61 static int pcap_rw_prepare_access(int fd, enum pcap_mode mode, bool jumbo)
  62 {
  63         set_ioprio_rt();
  64
  65         return 0;
  66 }
  67
  68 static void pcap_rw_fsync(int fd)
  69 {
  70         fdatasync(fd);
  71 }
  72
  73 const struct pcap_file_ops pcap_rw_ops = {
  74         .pull_fhdr_pcap = pcap_generic_pull_fhdr,
  75         .push_fhdr_pcap = pcap_generic_push_fhdr,
  76         .prepare_access_pcap = pcap_rw_prepare_access,
  77         .read_pcap = pcap_rw_read,
  78         .write_pcap = pcap_rw_write,
  79         .fsync_pcap = pcap_rw_fsync,
  80 };