view auto/os/linux @ 8913:40445fc7c403 quic

QUIC: fixed migration during NAT rebinding. The RFC 9000 allows a packet from known CID arrive from unknown path: These requirements regarding connection ID reuse apply only to the sending of packets, as unintentional changes in path without a change in connection ID are possible. For example, after a period of network inactivity, NAT rebinding might cause packets to be sent on a new path when the client resumes sending. Before the patch, such packets were rejected with an error in the ngx_quic_check_migration() function. Removing the check makes the separate function excessive - remaining checks are early migration check and "disable_active_migration" check. The latter is a transport parameter sent to client and it should not be used by server. The server should send "disable_active_migration" "if the endpoint does not support active connection migration" (18.2). The support status depends on nginx configuration: to have migration working with multiple workers, you need bpf helper, available on recent Linux systems. The patch does not set "disable_active_migration" automatically and leaves it for the administrator. By default, active migration is enabled. RFC 900 says that it is ok to migrate if the peer violates "disable_active_migration" flag requirements: If the peer violates this requirement, the endpoint MUST either drop the incoming packets on that path without generating a Stateless Reset OR proceed with path validation and allow the peer to migrate. Generating a Stateless Reset or closing the connection would allow third parties in the network to cause connections to close by spoofing or otherwise manipulating observed traffic. So, nginx adheres to the second option and proceeds to path validation. Note: The ngtcp2 may be used for testing both active migration and NAT rebinding: ngtcp2/client --change-local-addr=200ms --delay-stream=500ms <ip> <port> <url> ngtcp2/client --change-local-addr=200ms --delay-stream=500ms --nat-rebinding \ <ip> <port> <url>
author Vladimir Homutov <vl@nginx.com>
date Mon, 29 Nov 2021 11:51:14 +0300
parents bb5152ed045b
children 9ec96ceaf484
line wrap: on
line source


# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_LINUX . auto/have_headers

CORE_INCS="$UNIX_INCS"
CORE_DEPS="$UNIX_DEPS $LINUX_DEPS"
CORE_SRCS="$UNIX_SRCS $LINUX_SRCS"

ngx_spacer='
'

cc_aux_flags="$CC_AUX_FLAGS"
CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"


# Linux kernel version

version=$((`uname -r \
    | sed -n -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/ \
                                                 \1*256*256+\2*256+\3/p' \
             -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/\1*256*256+\2*256/p'`))

version=${version:-0}


# posix_fadvise64() had been implemented in 2.5.60

if [ $version -lt 132412 ]; then
    have=NGX_HAVE_POSIX_FADVISE . auto/nohave
fi

# epoll, EPOLLET version

ngx_feature="epoll"
ngx_feature_name="NGX_HAVE_EPOLL"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/epoll.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int efd = 0;
                  struct epoll_event ee;
                  ee.events = EPOLLIN|EPOLLOUT|EPOLLET;
                  ee.data.ptr = NULL;
                  (void) ee;
                  efd = epoll_create(100);
                  if (efd == -1) return 1;"
. auto/feature

if [ $ngx_found = yes ]; then
    have=NGX_HAVE_CLEAR_EVENT . auto/have
    CORE_SRCS="$CORE_SRCS $EPOLL_SRCS"
    EVENT_MODULES="$EVENT_MODULES $EPOLL_MODULE"
    EVENT_FOUND=YES


    # EPOLLRDHUP appeared in Linux 2.6.17, glibc 2.8

    ngx_feature="EPOLLRDHUP"
    ngx_feature_name="NGX_HAVE_EPOLLRDHUP"
    ngx_feature_run=no
    ngx_feature_incs="#include <sys/epoll.h>"
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="int efd = 0, fd = 0;
                      struct epoll_event ee;
                      ee.events = EPOLLIN|EPOLLRDHUP|EPOLLET;
                      ee.data.ptr = NULL;
                      epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)"
    . auto/feature


    # EPOLLEXCLUSIVE appeared in Linux 4.5, glibc 2.24

    ngx_feature="EPOLLEXCLUSIVE"
    ngx_feature_name="NGX_HAVE_EPOLLEXCLUSIVE"
    ngx_feature_run=no
    ngx_feature_incs="#include <sys/epoll.h>"
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="int efd = 0, fd = 0;
                      struct epoll_event ee;
                      ee.events = EPOLLIN|EPOLLEXCLUSIVE;
                      ee.data.ptr = NULL;
                      epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)"
    . auto/feature


    # eventfd()

    ngx_feature="eventfd()"
    ngx_feature_name="NGX_HAVE_EVENTFD"
    ngx_feature_run=no
    ngx_feature_incs="#include <sys/eventfd.h>"
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="(void) eventfd(0, 0)"
    . auto/feature

    if [ $ngx_found = yes ]; then
        have=NGX_HAVE_SYS_EVENTFD_H . auto/have
    fi


    if [ $ngx_found = no ]; then

        ngx_feature="eventfd() (SYS_eventfd)"
        ngx_feature_incs="#include <sys/syscall.h>"
        ngx_feature_test="(void) SYS_eventfd"
        . auto/feature
    fi
fi


# O_PATH and AT_EMPTY_PATH were introduced in 2.6.39, glibc 2.14

ngx_feature="O_PATH"
ngx_feature_name="NGX_HAVE_O_PATH"
ngx_feature_run=no
ngx_feature_incs="#include <sys/types.h>
                  #include <sys/stat.h>
                  #include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int fd; struct stat sb;
                  fd = openat(AT_FDCWD, \".\", O_PATH|O_DIRECTORY|O_NOFOLLOW);
                  if (fstatat(fd, \"\", &sb, AT_EMPTY_PATH) != 0) return 1"
. auto/feature


# sendfile()

CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE"
ngx_feature="sendfile()"
ngx_feature_name="NGX_HAVE_SENDFILE"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/sendfile.h>
                  #include <errno.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int s = 0, fd = 1;
                  ssize_t n; off_t off = 0;
                  n = sendfile(s, fd, &off, 1);
                  if (n == -1 && errno == ENOSYS) return 1"
. auto/feature

if [ $ngx_found = yes ]; then
    CORE_SRCS="$CORE_SRCS $LINUX_SENDFILE_SRCS"
fi


# sendfile64()

CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"
ngx_feature="sendfile64()"
ngx_feature_name="NGX_HAVE_SENDFILE64"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/sendfile.h>
                  #include <errno.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int s = 0, fd = 1;
                  ssize_t n; off_t off = 0;
                  n = sendfile(s, fd, &off, 1);
                  if (n == -1 && errno == ENOSYS) return 1"
. auto/feature


ngx_include="sys/prctl.h"; . auto/include

# prctl(PR_SET_DUMPABLE)

ngx_feature="prctl(PR_SET_DUMPABLE)"
ngx_feature_name="NGX_HAVE_PR_SET_DUMPABLE"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/prctl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) return 1"
. auto/feature


# prctl(PR_SET_KEEPCAPS)

ngx_feature="prctl(PR_SET_KEEPCAPS)"
ngx_feature_name="NGX_HAVE_PR_SET_KEEPCAPS"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/prctl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) return 1"
. auto/feature


# capabilities

ngx_feature="capabilities"
ngx_feature_name="NGX_HAVE_CAPABILITIES"
ngx_feature_run=no
ngx_feature_incs="#include <linux/capability.h>
                  #include <sys/syscall.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct __user_cap_data_struct    data;
                  struct __user_cap_header_struct  header;

                  header.version = _LINUX_CAPABILITY_VERSION_1;
                  data.effective = CAP_TO_MASK(CAP_NET_RAW);
                  data.permitted = 0;

                  (void) header;
                  (void) data;
                  (void) SYS_capset"
. auto/feature


# crypt_r()

ngx_feature="crypt_r()"
ngx_feature_name="NGX_HAVE_GNU_CRYPT_R"
ngx_feature_run=no
ngx_feature_incs="#include <crypt.h>"
ngx_feature_path=
ngx_feature_libs=-lcrypt
ngx_feature_test="struct crypt_data  cd;
                  crypt_r(\"key\", \"salt\", &cd);"
. auto/feature


ngx_include="sys/vfs.h";     . auto/include


CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"


# (E)BPF

ngx_feature="BPF support"
ngx_feature_name="NGX_HAVE_BPF"
ngx_feature_run=no
ngx_feature_incs="#include <linux/bpf.h>
                  #include <sys/syscall.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="
    union bpf_attr attr = { 0 };
    /* only declare BPF support if all required features found */
    attr.map_flags = 0;
    attr.map_type = BPF_MAP_TYPE_SOCKHASH;
    syscall(__NR_bpf, 0, &attr, 0);"

. auto/feature

if [ $ngx_found = yes ]; then
    BPF_FOUND=YES

    CORE_SRCS="$CORE_SRCS src/core/ngx_bpf.c"
    CORE_DEPS="$CORE_DEPS src/core/ngx_bpf.h"
fi


# SO_COOKIE socket option

ngx_feature="SO_COOKIE"
ngx_feature_name="NGX_HAVE_SO_COOKIE"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
                  #include <stdint.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="socklen_t optlen = sizeof(uint64_t);
              uint64_t cookie;
              getsockopt(0, SOL_SOCKET, SO_COOKIE, &cookie, &optlen)"
. auto/feature

if [ $ngx_found = yes ]; then
    SO_COOKIE_FOUND=YES
    have=NGX_HAVE_SO_COOKIE . auto/have
fi


# UDP_SEGMENT socket option is used for segmentation offloading

ngx_feature="UDP_SEGMENT"
ngx_feature_name="NGX_HAVE_UDP_SEGMENT"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
                  #include <stdint.h>
                  #include <netinet/udp.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="socklen_t optlen = sizeof(int);
              int val;
              getsockopt(0, SOL_UDP, UDP_SEGMENT, &val, &optlen)"
. auto/feature

if [ $ngx_found = yes ]; then
    UDP_SEGMENT_FOUND=YES
    have=NGX_HAVE_UDP_SEGMENT . auto/have
fi


# ngx_quic_bpf module uses sockhash to select socket from reuseport group,
# support appeared in Linux-5.7:
#
# commit: 9fed9000c5c6cacfcaaa48aff74818072ae294cc
# bpf: Allow selecting reuseport socket from a SOCKMAP/SOCKHASH
#
if [ $NGX_QUIC_BPF$BPF_FOUND = YESYES ]; then
    echo $ngx_n "checking for kernel with reuseport/BPF support...$ngx_c"
    if [ $version -lt 329472 ]; then
        echo " not found (at least 5.7 is required)"
        NGX_QUIC_BPF=NO
    else
        echo " found"
    fi
fi