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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 18:24:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 18:24:39 -0700
commit496322bc91e35007ed754184dcd447a02b6dd685 (patch)
treef5298d0a74c0a6e65c0e98050b594b8d020904c1 /Documentation/networking/packet_mmap.txt
parent2e17c5a97e231f3cb426f4b7895eab5be5c5442e (diff)
parent56e0ef527b184b3de2d7f88c6190812b2b2ac6bf (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: "This is a re-do of the net-next pull request for the current merge window. The only difference from the one I made the other day is that this has Eliezer's interface renames and the timeout handling changes made based upon your feedback, as well as a few bug fixes that have trickeled in. Highlights: 1) Low latency device polling, eliminating the cost of interrupt handling and context switches. Allows direct polling of a network device from socket operations, such as recvmsg() and poll(). Currently ixgbe, mlx4, and bnx2x support this feature. Full high level description, performance numbers, and design in commit 0a4db187a999 ("Merge branch 'll_poll'") From Eliezer Tamir. 2) With the routing cache removed, ip_check_mc_rcu() gets exercised more than ever before in the case where we have lots of multicast addresses. Use a hash table instead of a simple linked list, from Eric Dumazet. 3) Add driver for Atheros CQA98xx 802.11ac wireless devices, from Bartosz Markowski, Janusz Dziedzic, Kalle Valo, Marek Kwaczynski, Marek Puzyniak, Michal Kazior, and Sujith Manoharan. 4) Support reporting the TUN device persist flag to userspace, from Pavel Emelyanov. 5) Allow controlling network device VF link state using netlink, from Rony Efraim. 6) Support GRE tunneling in openvswitch, from Pravin B Shelar. 7) Adjust SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF for modern times, from Daniel Borkmann and Eric Dumazet. 8) Allow controlling of TCP quickack behavior on a per-route basis, from Cong Wang. 9) Several bug fixes and improvements to vxlan from Stephen Hemminger, Pravin B Shelar, and Mike Rapoport. In particular, support receiving on multiple UDP ports. 10) Major cleanups, particular in the area of debugging and cookie lifetime handline, to the SCTP protocol code. From Daniel Borkmann. 11) Allow packets to cross network namespaces when traversing tunnel devices. From Nicolas Dichtel. 12) Allow monitoring netlink traffic via AF_PACKET sockets, in a manner akin to how we monitor real network traffic via ptype_all. From Daniel Borkmann. 13) Several bug fixes and improvements for the new alx device driver, from Johannes Berg. 14) Fix scalability issues in the netem packet scheduler's time queue, by using an rbtree. From Eric Dumazet. 15) Several bug fixes in TCP loss recovery handling, from Yuchung Cheng. 16) Add support for GSO segmentation of MPLS packets, from Simon Horman. 17) Make network notifiers have a real data type for the opaque pointer that's passed into them. Use this to properly handle network device flag changes in arp_netdev_event(). From Jiri Pirko and Timo Teräs. 18) Convert several drivers over to module_pci_driver(), from Peter Huewe. 19) tcp_fixup_rcvbuf() can loop 500 times over loopback, just use a O(1) calculation instead. From Eric Dumazet. 20) Support setting of explicit tunnel peer addresses in ipv6, just like ipv4. From Nicolas Dichtel. 21) Protect x86 BPF JIT against spraying attacks, from Eric Dumazet. 22) Prevent a single high rate flow from overruning an individual cpu during RX packet processing via selective flow shedding. From Willem de Bruijn. 23) Don't use spinlocks in TCP md5 signing fast paths, from Eric Dumazet. 24) Don't just drop GSO packets which are above the TBF scheduler's burst limit, chop them up so they are in-bounds instead. Also from Eric Dumazet. 25) VLAN offloads are missed when configured on top of a bridge, fix from Vlad Yasevich. 26) Support IPV6 in ping sockets. From Lorenzo Colitti. 27) Receive flow steering targets should be updated at poll() time too, from David Majnemer. 28) Fix several corner case regressions in PMTU/redirect handling due to the routing cache removal, from Timo Teräs. 29) We have to be mindful of ipv4 mapped ipv6 sockets in upd_v6_push_pending_frames(). From Hannes Frederic Sowa. 30) Fix L2TP sequence number handling bugs, from James Chapman." * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1214 commits) drivers/net: caif: fix wrong rtnl_is_locked() usage drivers/net: enic: release rtnl_lock on error-path vhost-net: fix use-after-free in vhost_net_flush net: mv643xx_eth: do not use port number as platform device id net: sctp: confirm route during forward progress virtio_net: fix race in RX VQ processing virtio: support unlocked queue poll net/cadence/macb: fix bug/typo in extracting gem_irq_read_clear bit Documentation: Fix references to defunct linux-net@vger.kernel.org net/fs: change busy poll time accounting net: rename low latency sockets functions to busy poll bridge: fix some kernel warning in multicast timer sfc: Fix memory leak when discarding scattered packets sit: fix tunnel update via netlink dt:net:stmmac: Add dt specific phy reset callback support. dt:net:stmmac: Add support to dwmac version 3.610 and 3.710 dt:net:stmmac: Allocate platform data only if its NULL. net:stmmac: fix memleak in the open method ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available net: ipv6: fix wrong ping_v6_sendmsg return value ...
Diffstat (limited to 'Documentation/networking/packet_mmap.txt')
-rw-r--r--Documentation/networking/packet_mmap.txt133
1 files changed, 28 insertions, 105 deletions
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index 23dd80e82b8..8572796b1eb 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -704,6 +704,12 @@ So it seems to be a good candidate to be used with packet fanout.
Minimal example code by Daniel Borkmann based on Chetan Loke's lolpcap (compile
it with gcc -Wall -O2 blob.c, and try things like "./a.out eth0", etc.):
+/* Written from scratch, but kernel-to-user space API usage
+ * dissected from lolpcap:
+ * Copyright 2011, Chetan Loke <loke.chetan@gmail.com>
+ * License: GPL, version 2.0
+ */
+
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
@@ -722,27 +728,6 @@ it with gcc -Wall -O2 blob.c, and try things like "./a.out eth0", etc.):
#include <linux/if_ether.h>
#include <linux/ip.h>
-#define BLOCK_SIZE (1 << 22)
-#define FRAME_SIZE 2048
-
-#define NUM_BLOCKS 64
-#define NUM_FRAMES ((BLOCK_SIZE * NUM_BLOCKS) / FRAME_SIZE)
-
-#define BLOCK_RETIRE_TOV_IN_MS 64
-#define BLOCK_PRIV_AREA_SZ 13
-
-#define ALIGN_8(x) (((x) + 8 - 1) & ~(8 - 1))
-
-#define BLOCK_STATUS(x) ((x)->h1.block_status)
-#define BLOCK_NUM_PKTS(x) ((x)->h1.num_pkts)
-#define BLOCK_O2FP(x) ((x)->h1.offset_to_first_pkt)
-#define BLOCK_LEN(x) ((x)->h1.blk_len)
-#define BLOCK_SNUM(x) ((x)->h1.seq_num)
-#define BLOCK_O2PRIV(x) ((x)->offset_to_priv)
-#define BLOCK_PRIV(x) ((void *) ((uint8_t *) (x) + BLOCK_O2PRIV(x)))
-#define BLOCK_HDR_LEN (ALIGN_8(sizeof(struct block_desc)))
-#define BLOCK_PLUS_PRIV(sz_pri) (BLOCK_HDR_LEN + ALIGN_8((sz_pri)))
-
#ifndef likely
# define likely(x) __builtin_expect(!!(x), 1)
#endif
@@ -765,7 +750,7 @@ struct ring {
static unsigned long packets_total = 0, bytes_total = 0;
static sig_atomic_t sigint = 0;
-void sighandler(int num)
+static void sighandler(int num)
{
sigint = 1;
}
@@ -774,6 +759,8 @@ static int setup_socket(struct ring *ring, char *netdev)
{
int err, i, fd, v = TPACKET_V3;
struct sockaddr_ll ll;
+ unsigned int blocksiz = 1 << 22, framesiz = 1 << 11;
+ unsigned int blocknum = 64;
fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (fd < 0) {
@@ -788,13 +775,12 @@ static int setup_socket(struct ring *ring, char *netdev)
}
memset(&ring->req, 0, sizeof(ring->req));
- ring->req.tp_block_size = BLOCK_SIZE;
- ring->req.tp_frame_size = FRAME_SIZE;
- ring->req.tp_block_nr = NUM_BLOCKS;
- ring->req.tp_frame_nr = NUM_FRAMES;
- ring->req.tp_retire_blk_tov = BLOCK_RETIRE_TOV_IN_MS;
- ring->req.tp_sizeof_priv = BLOCK_PRIV_AREA_SZ;
- ring->req.tp_feature_req_word |= TP_FT_REQ_FILL_RXHASH;
+ ring->req.tp_block_size = blocksiz;
+ ring->req.tp_frame_size = framesiz;
+ ring->req.tp_block_nr = blocknum;
+ ring->req.tp_frame_nr = (blocksiz * blocknum) / framesiz;
+ ring->req.tp_retire_blk_tov = 60;
+ ring->req.tp_feature_req_word = TP_FT_REQ_FILL_RXHASH;
err = setsockopt(fd, SOL_PACKET, PACKET_RX_RING, &ring->req,
sizeof(ring->req));
@@ -804,8 +790,7 @@ static int setup_socket(struct ring *ring, char *netdev)
}
ring->map = mmap(NULL, ring->req.tp_block_size * ring->req.tp_block_nr,
- PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED,
- fd, 0);
+ PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED, fd, 0);
if (ring->map == MAP_FAILED) {
perror("mmap");
exit(1);
@@ -835,58 +820,6 @@ static int setup_socket(struct ring *ring, char *netdev)
return fd;
}
-#ifdef __checked
-static uint64_t prev_block_seq_num = 0;
-
-void assert_block_seq_num(struct block_desc *pbd)
-{
- if (unlikely(prev_block_seq_num + 1 != BLOCK_SNUM(pbd))) {
- printf("prev_block_seq_num:%"PRIu64", expected seq:%"PRIu64" != "
- "actual seq:%"PRIu64"\n", prev_block_seq_num,
- prev_block_seq_num + 1, (uint64_t) BLOCK_SNUM(pbd));
- exit(1);
- }
-
- prev_block_seq_num = BLOCK_SNUM(pbd);
-}
-
-static void assert_block_len(struct block_desc *pbd, uint32_t bytes, int block_num)
-{
- if (BLOCK_NUM_PKTS(pbd)) {
- if (unlikely(bytes != BLOCK_LEN(pbd))) {
- printf("block:%u with %upackets, expected len:%u != actual len:%u\n",
- block_num, BLOCK_NUM_PKTS(pbd), bytes, BLOCK_LEN(pbd));
- exit(1);
- }
- } else {
- if (unlikely(BLOCK_LEN(pbd) != BLOCK_PLUS_PRIV(BLOCK_PRIV_AREA_SZ))) {
- printf("block:%u, expected len:%lu != actual len:%u\n",
- block_num, BLOCK_HDR_LEN, BLOCK_LEN(pbd));
- exit(1);
- }
- }
-}
-
-static void assert_block_header(struct block_desc *pbd, const int block_num)
-{
- uint32_t block_status = BLOCK_STATUS(pbd);
-
- if (unlikely((block_status & TP_STATUS_USER) == 0)) {
- printf("block:%u, not in TP_STATUS_USER\n", block_num);
- exit(1);
- }
-
- assert_block_seq_num(pbd);
-}
-#else
-static inline void assert_block_header(struct block_desc *pbd, const int block_num)
-{
-}
-static void assert_block_len(struct block_desc *pbd, uint32_t bytes, int block_num)
-{
-}
-#endif
-
static void display(struct tpacket3_hdr *ppd)
{
struct ethhdr *eth = (struct ethhdr *) ((uint8_t *) ppd + ppd->tp_mac);
@@ -916,37 +849,27 @@ static void display(struct tpacket3_hdr *ppd)
static void walk_block(struct block_desc *pbd, const int block_num)
{
- int num_pkts = BLOCK_NUM_PKTS(pbd), i;
+ int num_pkts = pbd->h1.num_pkts, i;
unsigned long bytes = 0;
- unsigned long bytes_with_padding = BLOCK_PLUS_PRIV(BLOCK_PRIV_AREA_SZ);
struct tpacket3_hdr *ppd;
- assert_block_header(pbd, block_num);
-
- ppd = (struct tpacket3_hdr *) ((uint8_t *) pbd + BLOCK_O2FP(pbd));
+ ppd = (struct tpacket3_hdr *) ((uint8_t *) pbd +
+ pbd->h1.offset_to_first_pkt);
for (i = 0; i < num_pkts; ++i) {
bytes += ppd->tp_snaplen;
- if (ppd->tp_next_offset)
- bytes_with_padding += ppd->tp_next_offset;
- else
- bytes_with_padding += ALIGN_8(ppd->tp_snaplen + ppd->tp_mac);
-
display(ppd);
- ppd = (struct tpacket3_hdr *) ((uint8_t *) ppd + ppd->tp_next_offset);
- __sync_synchronize();
+ ppd = (struct tpacket3_hdr *) ((uint8_t *) ppd +
+ ppd->tp_next_offset);
}
- assert_block_len(pbd, bytes_with_padding, block_num);
-
packets_total += num_pkts;
bytes_total += bytes;
}
-void flush_block(struct block_desc *pbd)
+static void flush_block(struct block_desc *pbd)
{
- BLOCK_STATUS(pbd) = TP_STATUS_KERNEL;
- __sync_synchronize();
+ pbd->h1.block_status = TP_STATUS_KERNEL;
}
static void teardown_socket(struct ring *ring, int fd)
@@ -962,7 +885,7 @@ int main(int argc, char **argp)
socklen_t len;
struct ring ring;
struct pollfd pfd;
- unsigned int block_num = 0;
+ unsigned int block_num = 0, blocks = 64;
struct block_desc *pbd;
struct tpacket_stats_v3 stats;
@@ -984,15 +907,15 @@ int main(int argc, char **argp)
while (likely(!sigint)) {
pbd = (struct block_desc *) ring.rd[block_num].iov_base;
-retry_block:
- if ((BLOCK_STATUS(pbd) & TP_STATUS_USER) == 0) {
+
+ if ((pbd->h1.block_status & TP_STATUS_USER) == 0) {
poll(&pfd, 1, -1);
- goto retry_block;
+ continue;
}
walk_block(pbd, block_num);
flush_block(pbd);
- block_num = (block_num + 1) % NUM_BLOCKS;
+ block_num = (block_num + 1) % blocks;
}
len = sizeof(stats);