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 #ifndef PACKET_FANOUT
  30 # define PACKET_FANOUT                  18
  31 # define PACKET_FANOUT_POLICY_HASH      0
  32 # define PACKET_FANOUT_POLICY_LB        1
  33 # define PACKET_FANOUT_POLICY_DEFAULT   PACKET_FANOUT_HASH
  34 #endif
  35
  36 struct frame_map {
  37         struct tpacket2_hdr tp_h __aligned_tpacket;
  38         struct sockaddr_ll s_ll __align_tpacket(sizeof(struct tpacket2_hdr));
  39 };
  40
  41 struct ring {
  42         struct iovec *frames;
  43         uint8_t *mm_space;
  44         size_t mm_len;
  45         struct tpacket_req layout;
  46         struct sockaddr_ll s_ll;
  47 };
  48
  49 static inline void next_rnd_slot(unsigned int *it, struct ring *ring)
  50 {
  51         *it = rand() % ring->layout.tp_frame_nr;
  52 }
  53
  54 #define RING_SIZE_FALLBACK (1 << 26)
  55
  56 static inline unsigned int ring_size(char *ifname, unsigned int size)
  57 {
  58         if (size > 0)
  59                 return size;
  60
  61         /*
  62          * Device bitrate in bytes times two as ring size.
  63          *    Fallback => ~    64,00 MB
  64          *     10 MBit => ~     2,38 MB
  65          *     54 MBit => ~    12,88 MB
  66          *    100 MBit => ~    23,84 MB
  67          *    300 MBit => ~    71,52 MB
  68          *  1.000 MBit => ~   238,42 MB
  69          * 10.000 MBit => ~ 2.384.18 MB
  70          */
  71         size = device_bitrate(ifname);
  72         size = (size * 1000000) / 8;
  73         size = size * 2;
  74         if (size == 0)
  75                 size = RING_SIZE_FALLBACK;
  76
  77         return round_up_cacheline(size);
  78 }
  79
  80 static inline unsigned int ring_frame_size(struct ring *ring)
  81 {
  82         return ring->layout.tp_frame_size;
  83 }
  84
  85 static inline void tpacket_hdr_clone(struct tpacket2_hdr *thdrd,
  86                                      struct tpacket2_hdr *thdrs)
  87 {
  88         thdrd->tp_sec = thdrs->tp_sec;
  89         thdrd->tp_nsec = thdrs->tp_nsec;
  90         thdrd->tp_snaplen = thdrs->tp_snaplen;
  91         thdrd->tp_len = thdrs->tp_len;
  92 }
  93
  94 #ifndef POLLRDNORM
  95 # define POLLRDNORM     0x0040
  96 #endif
  97 #ifndef POLLWRNORM
  98 # define POLLWRNORM     0x0100
  99 #endif
 100 #ifndef POLLRDHUP
 101 # define POLLRDHUP      0x2000
 102 #endif
 103
 104 #define POLL_NEXT_PKT   0
 105 #define POLL_MOVE_OUT   1
 106
 107 static inline void prepare_polling(int sock, struct pollfd *pfd)
 108 {
 109         memset(pfd, 0, sizeof(*pfd));
 110         pfd->fd = sock;
 111         pfd->revents = 0;
 112         pfd->events = POLLIN | POLLRDNORM | POLLERR;
 113 }
 114
 115 static inline void set_sockopt_fanout(int sock, unsigned int fanout_id,
 116                                       unsigned int fanout_type)
 117 {
 118         unsigned int fanout_arg = (fanout_id | (fanout_type << 16));
 119         int ret = setsockopt(sock, SOL_PACKET, PACKET_FANOUT, &fanout_arg,
 120                              sizeof(fanout_arg));
 121         if (ret)
 122                 panic("No packet fanout support!\n");
 123 }
 124
 125 static inline void set_sockopt_tpacket(int sock)
 126 {
 127         int ret, val = TPACKET_V2;
 128
 129         ret = setsockopt(sock, SOL_PACKET, PACKET_VERSION, &val, sizeof(val));
 130         if (ret)
 131                 panic("Cannot set tpacketv2!\n");
 132 }
 133
 134 #endif /* RING_H */