ring_tx.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Copyright 2009, 2010 Emmanuel Roullit.
   5  * Copyright 2014, 2015 Tobias Klauser.
   6  * Subject to the GPL, version 2.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <sys/mman.h>
  14 #include <sys/types.h>
  15 #include <sys/socket.h>
  16 #include <arpa/inet.h>
  17 #include <linux/if_ether.h>
  18
  19 #include "die.h"
  20 #include "xmalloc.h"
  21 #include "ring_tx.h"
  22 #include "built_in.h"
  23
  24 static void set_packet_loss_discard(int sock)
  25 {
  26         int ret, discard = 1;
  27         ret = setsockopt(sock, SOL_PACKET, PACKET_LOSS, (void *) &discard,
  28                          sizeof(discard));
  29         if (ret < 0)
  30                 panic("setsockopt: cannot set packet loss");
  31 }
  32
  33 void destroy_tx_ring(int sock, struct ring *ring)
  34 {
  35         int ret;
  36
  37         munmap(ring->mm_space, ring->mm_len);
  38         ring->mm_len = 0;
  39
  40         fmemset(&ring->layout, 0, sizeof(ring->layout));
  41         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  42                          sizeof(ring->layout));
  43         if (unlikely(ret))
  44                 panic("Cannot destroy the TX_RING: %s!\n", strerror(errno));
  45
  46         xfree(ring->frames);
  47 }
  48
  49 static void setup_tx_ring_layout(int sock, struct ring *ring, size_t size,
  50                                  bool jumbo_support)
  51 {
  52         setup_ring_layout_generic(sock, ring, size, jumbo_support);
  53
  54         set_sockopt_tpacket_v2(sock);
  55
  56         ring_verify_layout(ring);
  57 }
  58
  59 static void create_tx_ring(int sock, struct ring *ring, bool verbose)
  60 {
  61         int ret;
  62 retry:
  63         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  64                          sizeof(ring->layout));
  65
  66         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  67                 shrink_ring_layout_generic(ring);
  68                 goto retry;
  69         }
  70
  71         if (ret < 0)
  72                 panic("Cannot allocate TX_RING!\n");
  73
  74         ring->mm_len = (size_t) ring->layout.tp_block_size * ring->layout.tp_block_nr;
  75
  76         if (verbose) {
  77                 printf("TX,V2: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  78                        (long double) ring->mm_len / (1 << 20),
  79                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  80         }
  81 }
  82
  83 static void alloc_tx_ring_frames(int sock __maybe_unused, struct ring *ring)
  84 {
  85         alloc_ring_frames_generic(ring, ring->layout.tp_frame_nr,
  86                                   ring->layout.tp_frame_size);
  87 }
  88
  89 void ring_tx_setup(struct ring *ring, int sock, size_t size, int ifindex,
  90                    bool jumbo_support, bool verbose)
  91 {
  92         fmemset(ring, 0, sizeof(*ring));
  93         set_packet_loss_discard(sock);
  94         setup_tx_ring_layout(sock, ring, size, jumbo_support);
  95         create_tx_ring(sock, ring, verbose);
  96         mmap_ring_generic(sock, ring);
  97         alloc_tx_ring_frames(sock, ring);
  98         bind_ring_generic(sock, ring, ifindex, true);
  99 }