ring.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Subject to the GPL, version 2.
   5  */
   6
   7 #ifndef RING_H
   8 #define RING_H
   9
  10 /*
  11  * "I love the smell of 10GbE in the morning. Smells like ... victory."
  12  *     - W. Richard Stevens, "Secret Teachings of the UNIX Environment"
  13  */
  14
  15 #include <stdio.h>
  16 #include <stdint.h>
  17 #include <linux/if_packet.h>
  18 #include <linux/socket.h>
  19 #include <linux/sockios.h>
  20 #include <sys/ioctl.h>
  21 #include <string.h>
  22 #include <poll.h>
  23 #include <sys/poll.h>
  24
  25 #include "xutils.h"
  26 #include "built_in.h"
  27 #include "die.h"
  28
  29 struct frame_map {
  30         struct tpacket2_hdr tp_h __aligned_tpacket;
  31         struct sockaddr_ll s_ll __align_tpacket(sizeof(struct tpacket2_hdr));
  32 };
  33
  34 struct ring {
  35         struct iovec *frames;
  36         uint8_t *mm_space;
  37         size_t mm_len;
  38         struct tpacket_req layout;
  39         struct sockaddr_ll s_ll;
  40 };
  41
  42 static inline void next_rnd_slot(unsigned int *it, struct ring *ring)
  43 {
  44         *it = rand() % ring->layout.tp_frame_nr;
  45 }
  46
  47 #define RING_SIZE_FALLBACK (1 << 26)
  48
  49 static inline unsigned int ring_size(char *ifname, unsigned int size)
  50 {
  51         if (size > 0)
  52                 return size;
  53
  54         /*
  55          * Device bitrate in bytes times two as ring size.
  56          *    Fallback => ~    64,00 MB
  57          *     10 MBit => ~     2,38 MB
  58          *     54 MBit => ~    12,88 MB
  59          *    100 MBit => ~    23,84 MB
  60          *    300 MBit => ~    71,52 MB
  61          *  1.000 MBit => ~   238,42 MB
  62          * 10.000 MBit => ~ 2.384.18 MB
  63          */
  64         size = device_bitrate(ifname);
  65         size = (size * 1000000) / 8;
  66         size = size * 2;
  67         if (size == 0)
  68                 size = RING_SIZE_FALLBACK;
  69
  70         return round_up_cacheline(size);
  71 }
  72
  73 static inline unsigned int ring_frame_size(struct ring *ring)
  74 {
  75         return ring->layout.tp_frame_size;
  76 }
  77
  78 static inline void tpacket_hdr_clone(struct tpacket2_hdr *thdrd,
  79                                      struct tpacket2_hdr *thdrs)
  80 {
  81         thdrd->tp_sec = thdrs->tp_sec;
  82         thdrd->tp_nsec = thdrs->tp_nsec;
  83         thdrd->tp_snaplen = thdrs->tp_snaplen;
  84         thdrd->tp_len = thdrs->tp_len;
  85 }
  86
  87 #ifndef POLLRDNORM
  88 # define POLLRDNORM     0x0040
  89 #endif
  90 #ifndef POLLWRNORM
  91 # define POLLWRNORM     0x0100
  92 #endif
  93 #ifndef POLLRDHUP
  94 # define POLLRDHUP      0x2000
  95 #endif
  96
  97 static inline void prepare_polling(int sock, struct pollfd *pfd)
  98 {
  99         memset(pfd, 0, sizeof(*pfd));
 100         pfd->fd = sock;
 101         pfd->revents = 0;
 102         pfd->events = POLLIN | POLLRDNORM | POLLERR;
 103 }
 104
 105 static inline void __set_sockopt_tpacket(int sock, int val)
 106 {
 107         int ret = setsockopt(sock, SOL_PACKET, PACKET_VERSION, &val, sizeof(val));
 108         if (ret)
 109                 panic("Cannot set tpacketv2!\n");
 110 }
 111
 112 static inline void set_sockopt_tpacket_v2(int sock)
 113 {
 114         __set_sockopt_tpacket(sock, TPACKET_V2);
 115 }
 116
 117 static inline void set_sockopt_tpacket_v3(int sock)
 118 {
 119         __set_sockopt_tpacket(sock, TPACKET_V3);
 120 }
 121
 122 #endif /* RING_H */