1. 18 5月, 2018 1 次提交
  2. 01 5月, 2018 1 次提交
  3. 24 4月, 2018 1 次提交
  4. 23 4月, 2018 3 次提交
    • Y
      net: init sk_cookie for inet socket · c6849a3a
      Yafang Shao 提交于
      With sk_cookie we can identify a socket, that is very helpful for
      traceing and statistic, i.e. tcp tracepiont and ebpf.
      So we'd better init it by default for inet socket.
      When using it, we just need call atomic64_read(&sk->sk_cookie).
      Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c6849a3a
    • Y
      net: introduce a new tracepoint for tcp_rcv_space_adjust · 6163849d
      Yafang Shao 提交于
      tcp_rcv_space_adjust is called every time data is copied to user space,
      introducing a tcp tracepoint for which could show us when the packet is
      copied to user.
      
      When a tcp packet arrives, tcp_rcv_established() will be called and with
      the existed tracepoint tcp_probe we could get the time when this packet
      arrives.
      Then this packet will be copied to user, and tcp_rcv_space_adjust will
      be called and with this new introduced tracepoint we could get the time
      when this packet is copied to user.
      With these two tracepoints, we could figure out whether the user program
      processes this packet immediately or there's latency.
      
      Hence in the printk message, sk_cookie is printed as a key to relate
      tcp_rcv_space_adjust with tcp_probe.
      
      Maybe we could export sockfd in this new tracepoint as well, then we
      could relate this new tracepoint with epoll/read/recv* tracepoints, and
      finally that could show us the whole lifespan of this packet. But we
      could also implement that with pid as these functions are executed in
      process context.
      Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6163849d
    • J
      tcp: don't read out-of-bounds opsize · 7e5a206a
      Jann Horn 提交于
      The old code reads the "opsize" variable from out-of-bounds memory (first
      byte behind the segment) if a broken TCP segment ends directly after an
      opcode that is neither EOL nor NOP.
      
      The result of the read isn't used for anything, so the worst thing that
      could theoretically happen is a pagefault; and since the physmap is usually
      mostly contiguous, even that seems pretty unlikely.
      
      The following C reproducer triggers the uninitialized read - however, you
      can't actually see anything happen unless you put something like a
      pr_warn() in tcp_parse_md5sig_option() to print the opsize.
      
      ====================================
      #define _GNU_SOURCE
      #include <arpa/inet.h>
      #include <stdlib.h>
      #include <errno.h>
      #include <stdarg.h>
      #include <net/if.h>
      #include <linux/if.h>
      #include <linux/ip.h>
      #include <linux/tcp.h>
      #include <linux/in.h>
      #include <linux/if_tun.h>
      #include <err.h>
      #include <sys/types.h>
      #include <sys/stat.h>
      #include <fcntl.h>
      #include <string.h>
      #include <stdio.h>
      #include <unistd.h>
      #include <sys/ioctl.h>
      #include <assert.h>
      
      void systemf(const char *command, ...) {
        char *full_command;
        va_list ap;
        va_start(ap, command);
        if (vasprintf(&full_command, command, ap) == -1)
          err(1, "vasprintf");
        va_end(ap);
        printf("systemf: <<<%s>>>\n", full_command);
        system(full_command);
      }
      
      char *devname;
      
      int tun_alloc(char *name) {
        int fd = open("/dev/net/tun", O_RDWR);
        if (fd == -1)
          err(1, "open tun dev");
        static struct ifreq req = { .ifr_flags = IFF_TUN|IFF_NO_PI };
        strcpy(req.ifr_name, name);
        if (ioctl(fd, TUNSETIFF, &req))
          err(1, "TUNSETIFF");
        devname = req.ifr_name;
        printf("device name: %s\n", devname);
        return fd;
      }
      
      #define IPADDR(a,b,c,d) (((a)<<0)+((b)<<8)+((c)<<16)+((d)<<24))
      
      void sum_accumulate(unsigned int *sum, void *data, int len) {
        assert((len&2)==0);
        for (int i=0; i<len/2; i++) {
          *sum += ntohs(((unsigned short *)data)[i]);
        }
      }
      
      unsigned short sum_final(unsigned int sum) {
        sum = (sum >> 16) + (sum & 0xffff);
        sum = (sum >> 16) + (sum & 0xffff);
        return htons(~sum);
      }
      
      void fix_ip_sum(struct iphdr *ip) {
        unsigned int sum = 0;
        sum_accumulate(&sum, ip, sizeof(*ip));
        ip->check = sum_final(sum);
      }
      
      void fix_tcp_sum(struct iphdr *ip, struct tcphdr *tcp) {
        unsigned int sum = 0;
        struct {
          unsigned int saddr;
          unsigned int daddr;
          unsigned char pad;
          unsigned char proto_num;
          unsigned short tcp_len;
        } fakehdr = {
          .saddr = ip->saddr,
          .daddr = ip->daddr,
          .proto_num = ip->protocol,
          .tcp_len = htons(ntohs(ip->tot_len) - ip->ihl*4)
        };
        sum_accumulate(&sum, &fakehdr, sizeof(fakehdr));
        sum_accumulate(&sum, tcp, tcp->doff*4);
        tcp->check = sum_final(sum);
      }
      
      int main(void) {
        int tun_fd = tun_alloc("inject_dev%d");
        systemf("ip link set %s up", devname);
        systemf("ip addr add 192.168.42.1/24 dev %s", devname);
      
        struct {
          struct iphdr ip;
          struct tcphdr tcp;
          unsigned char tcp_opts[20];
        } __attribute__((packed)) syn_packet = {
          .ip = {
            .ihl = sizeof(struct iphdr)/4,
            .version = 4,
            .tot_len = htons(sizeof(syn_packet)),
            .ttl = 30,
            .protocol = IPPROTO_TCP,
            /* FIXUP check */
            .saddr = IPADDR(192,168,42,2),
            .daddr = IPADDR(192,168,42,1)
          },
          .tcp = {
            .source = htons(1),
            .dest = htons(1337),
            .seq = 0x12345678,
            .doff = (sizeof(syn_packet.tcp)+sizeof(syn_packet.tcp_opts))/4,
            .syn = 1,
            .window = htons(64),
            .check = 0 /*FIXUP*/
          },
          .tcp_opts = {
            /* INVALID: trailing MD5SIG opcode after NOPs */
            1, 1, 1, 1, 1,
            1, 1, 1, 1, 1,
            1, 1, 1, 1, 1,
            1, 1, 1, 1, 19
          }
        };
        fix_ip_sum(&syn_packet.ip);
        fix_tcp_sum(&syn_packet.ip, &syn_packet.tcp);
        while (1) {
          int write_res = write(tun_fd, &syn_packet, sizeof(syn_packet));
          if (write_res != sizeof(syn_packet))
            err(1, "packet write failed");
        }
      }
      ====================================
      
      Fixes: cfb6eeb4 ("[TCP]: MD5 Signature Option (RFC2385) support.")
      Signed-off-by: NJann Horn <jannh@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7e5a206a
  5. 20 4月, 2018 4 次提交
  6. 17 4月, 2018 2 次提交
    • E
      tcp: avoid extra wakeups for SO_RCVLOWAT users · 03f45c88
      Eric Dumazet 提交于
      SO_RCVLOWAT is properly handled in tcp_poll(), so that POLLIN is only
      generated when enough bytes are available in receive queue, after
      David change (commit c7004482 "tcp: Respect SO_RCVLOWAT in tcp_poll().")
      
      But TCP still calls sk->sk_data_ready() for each chunk added in receive
      queue, meaning thread is awaken, and goes back to sleep shortly after.
      
      Tested:
      
      tcp_mmap test program, receiving 32768 MB of data with SO_RCVLOWAT set to 512KB
      
      -> Should get ~2 wakeups (c-switches) per MB, regardless of how many
      (tiny or big) packets were received.
      
      High speed (mostly full size GRO packets)
      
      received 32768 MB (100 % mmap'ed) in 8.03112 s, 34.2266 Gbit,
        cpu usage user:0.037 sys:1.404, 43.9758 usec per MB, 65497 c-switches
      
      received 32768 MB (99.9954 % mmap'ed) in 7.98453 s, 34.4263 Gbit,
        cpu usage user:0.03 sys:1.422, 44.3115 usec per MB, 65485 c-switches
      
      Low speed (sender is ratelimited and sends 1-MSS at a time, so GRO is not helping)
      
      received 22474.5 MB (100 % mmap'ed) in 6015.35 s, 0.0313414 Gbit,
        cpu usage user:0.05 sys:1.586, 72.7952 usec per MB, 44950 c-switches
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      03f45c88
    • E
      tcp: fix delayed acks behavior for SO_RCVLOWAT · 796f82ea
      Eric Dumazet 提交于
      We should not delay acks if there are not enough bytes
      in receive queue to satisfy SO_RCVLOWAT.
      
      Since [E]POLLIN event is not going to be generated, there is little
      hope for a delayed ack to be useful.
      
      In fact, delaying ACK prevents sender from completing
      the transfer.
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      796f82ea
  7. 26 3月, 2018 1 次提交
  8. 01 3月, 2018 3 次提交
  9. 22 2月, 2018 1 次提交
  10. 15 2月, 2018 1 次提交
    • E
      tcp: try to keep packet if SYN_RCV race is lost · e0f9759f
      Eric Dumazet 提交于
      배석진 reported that in some situations, packets for a given 5-tuple
      end up being processed by different CPUS.
      
      This involves RPS, and fragmentation.
      
      배석진 is seeing packet drops when a SYN_RECV request socket is
      moved into ESTABLISH state. Other states are protected by socket lock.
      
      This is caused by a CPU losing the race, and simply not caring enough.
      
      Since this seems to occur frequently, we can do better and perform
      a second lookup.
      
      Note that all needed memory barriers are already in the existing code,
      thanks to the spin_lock()/spin_unlock() pair in inet_ehash_insert()
      and reqsk_put(). The second lookup must find the new socket,
      unless it has already been accepted and closed by another cpu.
      
      Note that the fragmentation could be avoided in the first place by
      use of a correct TCP MSS option in the SYN{ACK} packet, but this
      does not mean we can not be more robust.
      
      Many thanks to 배석진 for a very detailed analysis.
      Reported-by: N배석진 <soukjin.bae@samsung.com>
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e0f9759f
  11. 12 2月, 2018 1 次提交
    • L
      vfs: do bulk POLL* -> EPOLL* replacement · a9a08845
      Linus Torvalds 提交于
      This is the mindless scripted replacement of kernel use of POLL*
      variables as described by Al, done by this script:
      
          for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
              L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
              for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
          done
      
      with de-mangling cleanups yet to come.
      
      NOTE! On almost all architectures, the EPOLL* constants have the same
      values as the POLL* constants do.  But they keyword here is "almost".
      For various bad reasons they aren't the same, and epoll() doesn't
      actually work quite correctly in some cases due to this on Sparc et al.
      
      The next patch from Al will sort out the final differences, and we
      should be all done.
      Scripted-by: NAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a9a08845
  12. 20 1月, 2018 2 次提交
  13. 03 1月, 2018 1 次提交
  14. 14 12月, 2017 1 次提交
  15. 12 12月, 2017 3 次提交
  16. 09 12月, 2017 1 次提交
  17. 08 12月, 2017 2 次提交
  18. 19 11月, 2017 1 次提交
    • N
      tcp: when scheduling TLP, time of RTO should account for current ACK · ed66dfaf
      Neal Cardwell 提交于
      Fix the TLP scheduling logic so that when scheduling a TLP probe, we
      ensure that the estimated time at which an RTO would fire accounts for
      the fact that ACKs indicating forward progress should push back RTO
      times.
      
      After the following fix:
      
      df92c839 ("tcp: fix xmit timer to only be reset if data ACKed/SACKed")
      
      we had an unintentional behavior change in the following kind of
      scenario: suppose the RTT variance has been very low recently. Then
      suppose we send out a flight of N packets and our RTT is 100ms:
      
      t=0: send a flight of N packets
      t=100ms: receive an ACK for N-1 packets
      
      The response before df92c839 that was:
        -> schedule a TLP for now + RTO_interval
      
      The response after df92c839 is:
        -> schedule a TLP for t=0 + RTO_interval
      
      Since RTO_interval = srtt + RTT_variance, this means that we have
      scheduled a TLP timer at a point in the future that only accounts for
      RTT_variance. If the RTT_variance term is small, this means that the
      timer fires soon.
      
      Before df92c839 this would not happen, because in that code, when
      we receive an ACK for a prefix of flight, we did:
      
          1) Near the top of tcp_ack(), switch from TLP timer to RTO
             at write_queue_head->paket_tx_time + RTO_interval:
                  if (icsk->icsk_pending == ICSK_TIME_LOSS_PROBE)
                         tcp_rearm_rto(sk);
      
          2) In tcp_clean_rtx_queue(), update the RTO to now + RTO_interval:
                  if (flag & FLAG_ACKED) {
                         tcp_rearm_rto(sk);
      
          3) In tcp_ack() after tcp_fastretrans_alert() switch from RTO
             to TLP at now + RTO_interval:
                  if (icsk->icsk_pending == ICSK_TIME_RETRANS)
                         tcp_schedule_loss_probe(sk);
      
      In df92c839 we removed that 3-phase dance, and instead directly
      set the TLP timer once: we set the TLP timer in cases like this to
      write_queue_head->packet_tx_time + RTO_interval. So if the RTT
      variance is small, then this means that this is setting the TLP timer
      to fire quite soon. This means if the ACK for the tail of the flight
      takes longer than an RTT to arrive (often due to delayed ACKs), then
      the TLP timer fires too quickly.
      
      Fixes: df92c839 ("tcp: fix xmit timer to only be reset if data ACKed/SACKed")
      Signed-off-by: NNeal Cardwell <ncardwell@google.com>
      Signed-off-by: NYuchung Cheng <ycheng@google.com>
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ed66dfaf
  19. 16 11月, 2017 1 次提交
  20. 15 11月, 2017 1 次提交
    • E
      tcp: highest_sack fix · 50895b9d
      Eric Dumazet 提交于
      syzbot easily found a regression added in our latest patches [1]
      
      No longer set tp->highest_sack to the head of the send queue since
      this is not logical and error prone.
      
      Only sack processing should maintain the pointer to an skb from rtx queue.
      
      We might in the future only remember the sequence instead of a pointer to skb,
      since rb-tree should allow a fast lookup.
      
      [1]
      BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1706 [inline]
      BUG: KASAN: use-after-free in tcp_ack+0x42bb/0x4fd0 net/ipv4/tcp_input.c:3537
      Read of size 4 at addr ffff8801c154faa8 by task syz-executor4/12860
      
      CPU: 0 PID: 12860 Comm: syz-executor4 Not tainted 4.14.0-next-20171113+ #41
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:17 [inline]
       dump_stack+0x194/0x257 lib/dump_stack.c:53
       print_address_description+0x73/0x250 mm/kasan/report.c:252
       kasan_report_error mm/kasan/report.c:351 [inline]
       kasan_report+0x25b/0x340 mm/kasan/report.c:409
       __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
       tcp_highest_sack_seq include/net/tcp.h:1706 [inline]
       tcp_ack+0x42bb/0x4fd0 net/ipv4/tcp_input.c:3537
       tcp_rcv_established+0x672/0x18a0 net/ipv4/tcp_input.c:5439
       tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1468
       sk_backlog_rcv include/net/sock.h:909 [inline]
       __release_sock+0x124/0x360 net/core/sock.c:2264
       release_sock+0xa4/0x2a0 net/core/sock.c:2778
       tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1462
       inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
       sock_sendmsg_nosec net/socket.c:632 [inline]
       sock_sendmsg+0xca/0x110 net/socket.c:642
       ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2048
       __sys_sendmsg+0xe5/0x210 net/socket.c:2082
       SYSC_sendmsg net/socket.c:2093 [inline]
       SyS_sendmsg+0x2d/0x50 net/socket.c:2089
       entry_SYSCALL_64_fastpath+0x1f/0x96
      RIP: 0033:0x452879
      RSP: 002b:00007fc9761bfbe8 EFLAGS: 00000212 ORIG_RAX: 000000000000002e
      RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452879
      RDX: 0000000000000000 RSI: 0000000020917fc8 RDI: 0000000000000015
      RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee3a0
      R13: 00000000ffffffff R14: 00007fc9761c06d4 R15: 0000000000000000
      
      Allocated by task 12860:
       save_stack+0x43/0xd0 mm/kasan/kasan.c:447
       set_track mm/kasan/kasan.c:459 [inline]
       kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
       kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
       kmem_cache_alloc_node+0x144/0x760 mm/slab.c:3638
       __alloc_skb+0xf1/0x780 net/core/skbuff.c:193
       alloc_skb_fclone include/linux/skbuff.h:1023 [inline]
       sk_stream_alloc_skb+0x11d/0x900 net/ipv4/tcp.c:870
       tcp_sendmsg_locked+0x1341/0x3b80 net/ipv4/tcp.c:1299
       tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461
       inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
       sock_sendmsg_nosec net/socket.c:632 [inline]
       sock_sendmsg+0xca/0x110 net/socket.c:642
       SYSC_sendto+0x358/0x5a0 net/socket.c:1749
       SyS_sendto+0x40/0x50 net/socket.c:1717
       entry_SYSCALL_64_fastpath+0x1f/0x96
      
      Freed by task 12860:
       save_stack+0x43/0xd0 mm/kasan/kasan.c:447
       set_track mm/kasan/kasan.c:459 [inline]
       kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
       __cache_free mm/slab.c:3492 [inline]
       kmem_cache_free+0x77/0x280 mm/slab.c:3750
       kfree_skbmem+0xdd/0x1d0 net/core/skbuff.c:603
       __kfree_skb+0x1d/0x20 net/core/skbuff.c:642
       sk_wmem_free_skb include/net/sock.h:1419 [inline]
       tcp_rtx_queue_unlink_and_free include/net/tcp.h:1682 [inline]
       tcp_clean_rtx_queue net/ipv4/tcp_input.c:3111 [inline]
       tcp_ack+0x1b17/0x4fd0 net/ipv4/tcp_input.c:3593
       tcp_rcv_established+0x672/0x18a0 net/ipv4/tcp_input.c:5439
       tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1468
       sk_backlog_rcv include/net/sock.h:909 [inline]
       __release_sock+0x124/0x360 net/core/sock.c:2264
       release_sock+0xa4/0x2a0 net/core/sock.c:2778
       tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1462
       inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
       sock_sendmsg_nosec net/socket.c:632 [inline]
       sock_sendmsg+0xca/0x110 net/socket.c:642
       ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2048
       __sys_sendmsg+0xe5/0x210 net/socket.c:2082
       SYSC_sendmsg net/socket.c:2093 [inline]
       SyS_sendmsg+0x2d/0x50 net/socket.c:2089
       entry_SYSCALL_64_fastpath+0x1f/0x96
      
      The buggy address belongs to the object at ffff8801c154fa80
       which belongs to the cache skbuff_fclone_cache of size 456
      The buggy address is located 40 bytes inside of
       456-byte region [ffff8801c154fa80, ffff8801c154fc48)
      The buggy address belongs to the page:
      page:ffffea00070553c0 count:1 mapcount:0 mapping:ffff8801c154f080 index:0x0
      flags: 0x2fffc0000000100(slab)
      raw: 02fffc0000000100 ffff8801c154f080 0000000000000000 0000000100000006
      raw: ffffea00070a5a20 ffffea0006a18360 ffff8801d9ca0500 0000000000000000
      page dumped because: kasan: bad access detected
      
      Fixes: 737ff314 ("tcp: use sequence distance to detect reordering")
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Cc: Yuchung Cheng <ycheng@google.com>
      Reported-by: Nsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      50895b9d
  21. 11 11月, 2017 2 次提交
  22. 10 11月, 2017 2 次提交
  23. 05 11月, 2017 2 次提交
    • P
      tcp: fix DSACK-based undo on non-duplicate ACK · d09b9e60
      Priyaranjan Jha 提交于
      Fixes DSACK-based undo when sender is in Open State and
      an ACK advances snd_una.
      
      Example scenario:
      - Sender goes into recovery and makes some spurious rtx.
      - It comes out of recovery and enters into open state.
      - It sends some more packets, let's say 4.
      - The receiver sends an ACK for the first two, but this ACK is lost.
      - The sender receives ack for first two, and DSACK for previous
        spurious rtx.
      Signed-off-by: NPriyaranjan Jha <priyarjha@google.com>
      Signed-off-by: NYuchung Cheng <ycheng@google.com>
      Signed-off-by: NNeal Cardwell <ncardwell@google.com>
      Acked-by: NYousuk Seung <ysseung@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d09b9e60
    • P
      tcp: higher throughput under reordering with adaptive RACK reordering wnd · 1f255691
      Priyaranjan Jha 提交于
      Currently TCP RACK loss detection does not work well if packets are
      being reordered beyond its static reordering window (min_rtt/4).Under
      such reordering it may falsely trigger loss recoveries and reduce TCP
      throughput significantly.
      
      This patch improves that by increasing and reducing the reordering
      window based on DSACK, which is now supported in major TCP implementations.
      It makes RACK's reo_wnd adaptive based on DSACK and no. of recoveries.
      
      - If DSACK is received, increment reo_wnd by min_rtt/4 (upper bounded
        by srtt), since there is possibility that spurious retransmission was
        due to reordering delay longer than reo_wnd.
      
      - Persist the current reo_wnd value for TCP_RACK_RECOVERY_THRESH (16)
        no. of successful recoveries (accounts for full DSACK-based loss
        recovery undo). After that, reset it to default (min_rtt/4).
      
      - At max, reo_wnd is incremented only once per rtt. So that the new
        DSACK on which we are reacting, is due to the spurious retx (approx)
        after the reo_wnd has been updated last time.
      
      - reo_wnd is tracked in terms of steps (of min_rtt/4), rather than
        absolute value to account for change in rtt.
      
      In our internal testing, we observed significant increase in throughput,
      in scenarios where reordering exceeds min_rtt/4 (previous static value).
      Signed-off-by: NPriyaranjan Jha <priyarjha@google.com>
      Signed-off-by: NYuchung Cheng <ycheng@google.com>
      Signed-off-by: NNeal Cardwell <ncardwell@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1f255691
  24. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman 提交于
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  25. 29 10月, 2017 1 次提交
    • D
      tcp: Remove "linux/unaligned/access_ok.h" include. · 949cf8b1
      David S. Miller 提交于
      This causes build failures:
      
      In file included from net/ipv4/tcp_input.c:79:0:
      ./include/linux/unaligned/access_ok.h:7:28: error: redefinition of
      'get_unaligned_le16'
      In file included from ./include/asm-generic/unaligned.h:17:0,
                       from ./arch/arm/include/generated/asm/unaligned.h:1,
                       from net/ipv4/tcp_input.c:76:
      ./include/linux/unaligned/le_struct.h:6:19: note: previous definition
      of 'get_unaligned_le16' was here
      In file included from net/ipv4/tcp_input.c:79:0:
      ./include/linux/unaligned/access_ok.h:12:28: error: redefinition of
      'get_unaligned_le32'
      
      Plain "asm/access_ok.h", which is already included, is
      sufficient.
      
      Fixes: 60e2a778 ("tcp: TCP experimental option for SMC")
      Reported-by: NEgil Hjelmeland <privat@egil-hjelmeland.no>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      949cf8b1