src/ring.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2009, 2010 Daniel Borkmann.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #ifndef RING_H
   9 #define RING_H
  10
  11 /*
  12  * "I love the smell of 10GbE in the morning. Smells like ... victory."
  13  *     - W. Richard Stevens, "Secret Teachings of the UNIX Environment"
  14  */
  15
  16 #include <stdio.h>
  17 #include <stdint.h>
  18 #include <linux/if_packet.h>
  19 #include <string.h>
  20 #include <poll.h>
  21 #include <sys/poll.h>
  22
  23 #include "xsys.h"
  24 #include "built_in.h"
  25 #include "mtrand.h"
  26 #include "die.h"
  27
  28 #ifndef PACKET_FANOUT
  29 # define PACKET_FANOUT          18
  30 # define PACKET_FANOUT_HASH     0
  31 # define PACKET_FANOUT_LB       1
  32 #endif
  33
  34 struct frame_map {
  35         struct tpacket_hdr tp_h __aligned_tpacket;
  36         struct sockaddr_ll s_ll __aligned_tpacket;
  37 };
  38
  39 struct ring {
  40         struct iovec *frames __cacheline_aligned;
  41         uint8_t *mm_space __cacheline_aligned;
  42         size_t mm_len;
  43         struct tpacket_req layout;
  44         struct sockaddr_ll s_ll;
  45 };
  46
  47 static inline void next_slot(unsigned int *it, struct ring *ring)
  48 {
  49         (*it)++;
  50         atomic_cmp_swp(it, ring->layout.tp_frame_nr, 0);
  51 }
  52
  53 static inline void next_slot_prerd(unsigned int *it, struct ring *ring)
  54 {
  55         (*it)++;
  56         atomic_cmp_swp(it, ring->layout.tp_frame_nr, 0);
  57         prefetch_rd_hi(ring->frames[*it].iov_base);
  58 }
  59
  60 static inline void next_slot_prewr(unsigned int *it, struct ring *ring)
  61 {
  62         (*it)++;
  63         atomic_cmp_swp(it, ring->layout.tp_frame_nr, 0);
  64         prefetch_wr_hi(ring->frames[*it].iov_base);
  65 }
  66
  67 static inline void next_rnd_slot(unsigned int *it, struct ring *ring)
  68 {
  69         *it = mt_rand_int32() % ring->layout.tp_frame_nr;
  70 }
  71
  72 #define RING_SIZE_FALLBACK (1 << 26)
  73
  74 static inline unsigned int ring_size(char *ifname, unsigned int size)
  75 {
  76         if (size > 0)
  77                 return size;
  78
  79         /*
  80          * Device bitrate in bytes times two as ring size.
  81          *    Fallback => ~    64,00 MB
  82          *     10 MBit => ~     2,38 MB
  83          *     54 MBit => ~    12,88 MB
  84          *    100 MBit => ~    23,84 MB
  85          *    300 MBit => ~    71,52 MB
  86          *  1.000 MBit => ~   238,42 MB
  87          * 10.000 MBit => ~ 2.384.18 MB
  88          */
  89         size = device_bitrate(ifname);
  90         size = (size * 1000000) / 8;
  91         size = size * 2;
  92         if (size == 0)
  93                 size = RING_SIZE_FALLBACK;
  94         return round_up_cacheline(size);
  95 }
  96
  97 enum ring_mode {
  98         RING_MODE_EGRESS,
  99         RING_MODE_INGRESS,
 100 };
 101
 102 static inline unsigned int ring_frame_size(struct ring *ring)
 103 {
 104         return ring->layout.tp_frame_size;
 105 }
 106
 107 static inline void tpacket_hdr_clone(struct tpacket_hdr *thdrd,
 108                                      struct tpacket_hdr *thdrs)
 109 {
 110         thdrd->tp_sec = thdrs->tp_sec;
 111         thdrd->tp_usec = thdrs->tp_usec;
 112         thdrd->tp_snaplen = thdrs->tp_snaplen;
 113         thdrd->tp_len = thdrs->tp_len;
 114 }
 115
 116 #ifndef POLLRDNORM
 117 # define POLLRDNORM     0x0040
 118 #endif
 119 #ifndef POLLWRNORM
 120 # define POLLWRNORM     0x0100
 121 #endif
 122 #ifndef POLLRDHUP
 123 # define POLLRDHUP      0x2000
 124 #endif
 125
 126 #define POLL_NEXT_PKT   0
 127 #define POLL_MOVE_OUT   1
 128
 129 static inline void prepare_polling(int sock, struct pollfd *pfd)
 130 {
 131         memset(pfd, 0, sizeof(*pfd));
 132         pfd->fd = sock;
 133         pfd->revents = 0;
 134         pfd->events = POLLIN | POLLRDNORM | POLLERR;
 135 }
 136
 137 static inline void set_sockopt_fanout(int sock, unsigned int fanout_id,
 138                                       unsigned int fanout_type)
 139 {
 140         unsigned int fanout_arg = (fanout_id | (fanout_type << 16));
 141         int ret = setsockopt(sock, SOL_PACKET, PACKET_FANOUT, &fanout_arg,
 142                              sizeof(fanout_arg));
 143         if (ret)
 144                 panic("No packet fanout support!\n");
 145 }
 146
 147 #endif /* RING_H */