pcap_rw.c

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