path: root/source/l/libuv/libuv.977be04762b9bda29a88d39bb3e2cb7c44b2ad22.patch

From 977be04762b9bda29a88d39bb3e2cb7c44b2ad22 Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Thu, 16 Apr 2020 09:59:03 +0200
Subject: [PATCH] Revert "freebsd,linux: add recvmmsg() + sendmmsg() udp
 implementation"

This reverts commit 3d7136639a39db46bc4a9074922559a564e49514.
This reverts commit d9cd7d437d6bcea56355b6e0ef215aa64687d7a1.

The first reverted commit is the sendmmsg/recvmmsg support, the second
one a fix-up to deliver datagrams in order. The second commit has been
implicated in causing bind9 to crash on freebsd.

A quick review of the code suggests that downstream code written against
pre-v1.35.0 libuv can't safely deal with multi-datagram support because
they are unaware of the `UV_UDP_MMSG_CHUNK` flag and what that implies
for buffer management, hence I'm moving to revert it.

The `UV_UDP_MMSG_CHUNK` flag remains part of `uv_udp_flags` for
API/ABI backwards compatibility reasons but it is no longer used.

Fixes: https://github.com/libuv/libuv/issues/2791
Refs: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=245653
---
 docs/src/udp.rst          |  18 +---
 include/uv.h              |   5 +-
 src/unix/freebsd.c        |  25 -----
 src/unix/internal.h       |  24 -----
 src/unix/linux-syscalls.c |   1 -
 src/unix/linux-syscalls.h |  14 +++
 src/unix/udp.c            | 207 +-------------------------------------
 7 files changed, 22 insertions(+), 272 deletions(-)

diff --git a/docs/src/udp.rst b/docs/src/udp.rst
index 786a28b030..53b1fea493 100644
--- a/docs/src/udp.rst
+++ b/docs/src/udp.rst
@@ -42,11 +42,6 @@ Data types
             * any traffic, in effect "stealing" the port from the previous listener.
             */
             UV_UDP_REUSEADDR = 4
-            /*
-             * Indicates that the message was received by recvmmsg, so the buffer provided
-             * must not be freed by the recv_cb callback.
-             */
-            UV_UDP_MMSG_CHUNK = 8
         };
 
 .. c:type:: void (*uv_udp_send_cb)(uv_udp_send_t* req, int status)
@@ -67,18 +62,13 @@ Data types
     * `buf`: :c:type:`uv_buf_t` with the received data.
     * `addr`: ``struct sockaddr*`` containing the address of the sender.
       Can be NULL. Valid for the duration of the callback only.
-    * `flags`: One or more or'ed UV_UDP_* constants.
+    * `flags`: One or more or'ed UV_UDP_* constants. Right now only
+      ``UV_UDP_PARTIAL`` is used.
 
     The callee is responsible for freeing the buffer, libuv does not reuse it.
     The buffer may be a null buffer (where `buf->base` == NULL and `buf->len` == 0)
     on error.
 
-    When using :man:`recvmmsg(2)`, chunks will have the `UV_UDP_MMSG_CHUNK` flag set,
-    those must not be freed. There will be a final callback with `nread` set to 0,
-    `addr` set to NULL and the buffer pointing at the initially allocated data with
-    the `UV_UDP_MMSG_CHUNK` flag cleared. This is a good chance for the callee to
-    free the provided buffer.
-
     .. note::
         The receive callback will be called with `nread` == 0 and `addr` == NULL when there is
         nothing to read, and with `nread` == 0 and `addr` != NULL when an empty UDP packet is
@@ -376,10 +366,6 @@ API
 
     :returns: 0 on success, or an error code < 0 on failure.
 
-    .. versionchanged:: 1.35.0 added support for :man:`recvmmsg(2)` on supported platforms).
-                        The use of this feature requires a buffer larger than
-                        2 * 64KB to be passed to `alloc_cb`.
-
 .. c:function:: int uv_udp_recv_stop(uv_udp_t* handle)
 
     Stop listening for incoming datagrams.
diff --git a/include/uv.h b/include/uv.h
index 2e8072fdae..dd8c8a40b0 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -1,4 +1,4 @@
-/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+/* COPYRIGHT JOYENT, INC. AND OTHER NODE CONTRIBUTORS. ALL RIGHTS RESERVED.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to
@@ -607,8 +607,7 @@ enum uv_udp_flags {
    */
   UV_UDP_REUSEADDR = 4,
   /*
-   * Indicates that the message was received by recvmmsg, so the buffer provided
-   * must not be freed by the recv_cb callback.
+   * Unused. Here for API/ABI compatibility.
    */
   UV_UDP_MMSG_CHUNK = 8
 };
diff --git a/src/unix/freebsd.c b/src/unix/freebsd.c
index ef77e127c2..57bd04e240 100644
--- a/src/unix/freebsd.c
+++ b/src/unix/freebsd.c
@@ -288,28 +288,3 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
   uv__free(cp_times);
   return 0;
 }
-
-
-int uv__sendmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags) {
-#if __FreeBSD__ >= 11
-  return sendmmsg(fd, mmsg, vlen, flags);
-#else
-  return errno = ENOSYS, -1;
-#endif
-}
-
-
-int uv__recvmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags,
-                 struct timespec* timeout) {
-#if __FreeBSD__ >= 11
-  return recvmmsg(fd, mmsg, vlen, flags, timeout);
-#else
-  return errno = ENOSYS, -1;
-#endif
-}
diff --git a/src/unix/internal.h b/src/unix/internal.h
index 598554b607..469fd7d2b8 100644
--- a/src/unix/internal.h
+++ b/src/unix/internal.h
@@ -31,7 +31,6 @@
 #include <fcntl.h>  /* O_CLOEXEC and O_NONBLOCK, if supported. */
 #include <stdio.h>
 #include <errno.h>
-#include <sys/socket.h>
 
 #if defined(__STRICT_ANSI__)
 # define inline __inline
@@ -328,27 +327,4 @@ int uv__getsockpeername(const uv_handle_t* handle,
                         struct sockaddr* name,
                         int* namelen);
 
-#if defined(__linux__)            ||                                      \
-    defined(__FreeBSD__)          ||                                      \
-    defined(__FreeBSD_kernel__)
-#define HAVE_MMSG 1
-struct uv__mmsghdr {
-  struct msghdr msg_hdr;
-  unsigned int msg_len;
-};
-
-int uv__recvmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags,
-                 struct timespec* timeout);
-int uv__sendmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags);
-#else
-#define HAVE_MMSG 0
-#endif
-
-
 #endif /* UV_UNIX_INTERNAL_H_ */
diff --git a/src/unix/linux-syscalls.c b/src/unix/linux-syscalls.c
index 742f26ada8..eb5a8fd274 100644
--- a/src/unix/linux-syscalls.c
+++ b/src/unix/linux-syscalls.c
@@ -126,7 +126,6 @@
 # endif
 #endif /* __NR_getrandom */
 
-struct uv__mmsghdr;
 
 int uv__sendmmsg(int fd,
                  struct uv__mmsghdr* mmsg,
diff --git a/src/unix/linux-syscalls.h b/src/unix/linux-syscalls.h
index 2e8fa2a519..7ee1511a45 100644
--- a/src/unix/linux-syscalls.h
+++ b/src/unix/linux-syscalls.h
@@ -61,6 +61,20 @@ struct uv__statx {
   uint64_t unused1[14];
 };
 
+struct uv__mmsghdr {
+  struct msghdr msg_hdr;
+  unsigned int msg_len;
+};
+
+int uv__recvmmsg(int fd,
+                 struct uv__mmsghdr* mmsg,
+                 unsigned int vlen,
+                 unsigned int flags,
+                 struct timespec* timeout);
+int uv__sendmmsg(int fd,
+                 struct uv__mmsghdr* mmsg,
+                 unsigned int vlen,
+                 unsigned int flags);
 ssize_t uv__preadv(int fd, const struct iovec *iov, int iovcnt, int64_t offset);
 ssize_t uv__pwritev(int fd, const struct iovec *iov, int iovcnt, int64_t offset);
 int uv__dup3(int oldfd, int newfd, int flags);
diff --git a/src/unix/udp.c b/src/unix/udp.c
index f2fcae1760..982059ff48 100644
--- a/src/unix/udp.c
+++ b/src/unix/udp.c
@@ -32,8 +32,6 @@
 #endif
 #include <sys/un.h>
 
-#define UV__UDP_DGRAM_MAXSIZE (64 * 1024)
-
 #if defined(IPV6_JOIN_GROUP) && !defined(IPV6_ADD_MEMBERSHIP)
 # define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
 #endif
@@ -51,36 +49,6 @@ static int uv__udp_maybe_deferred_bind(uv_udp_t* handle,
                                        int domain,
                                        unsigned int flags);
 
-#if HAVE_MMSG
-
-#define UV__MMSG_MAXWIDTH 20
-
-static int uv__udp_recvmmsg(uv_udp_t* handle, uv_buf_t* buf);
-static void uv__udp_sendmmsg(uv_udp_t* handle);
-
-static int uv__recvmmsg_avail;
-static int uv__sendmmsg_avail;
-static uv_once_t once = UV_ONCE_INIT;
-
-static void uv__udp_mmsg_init(void) {
-  int ret;
-  int s;
-  s = uv__socket(AF_INET, SOCK_DGRAM, 0);
-  if (s < 0)
-    return;
-  ret = uv__sendmmsg(s, NULL, 0, 0);
-  if (ret == 0 || errno != ENOSYS) {
-    uv__sendmmsg_avail = 1;
-    uv__recvmmsg_avail = 1;
-  } else {
-    ret = uv__recvmmsg(s, NULL, 0, 0, NULL);
-    if (ret == 0 || errno != ENOSYS)
-      uv__recvmmsg_avail = 1;
-  }
-  uv__close(s);
-}
-
-#endif
 
 void uv__udp_close(uv_udp_t* handle) {
   uv__io_close(handle->loop, &handle->io_watcher);
@@ -180,61 +148,6 @@ static void uv__udp_io(uv_loop_t* loop, uv__io_t* w, unsigned int revents) {
   }
 }
 
-#if HAVE_MMSG
-static int uv__udp_recvmmsg(uv_udp_t* handle, uv_buf_t* buf) {
-  struct sockaddr_in6 peers[UV__MMSG_MAXWIDTH];
-  struct iovec iov[UV__MMSG_MAXWIDTH];
-  struct uv__mmsghdr msgs[UV__MMSG_MAXWIDTH];
-  ssize_t nread;
-  uv_buf_t chunk_buf;
-  size_t chunks;
-  int flags;
-  size_t k;
-
-  /* prepare structures for recvmmsg */
-  chunks = buf->len / UV__UDP_DGRAM_MAXSIZE;
-  if (chunks > ARRAY_SIZE(iov))
-    chunks = ARRAY_SIZE(iov);
-  for (k = 0; k < chunks; ++k) {
-    iov[k].iov_base = buf->base + k * UV__UDP_DGRAM_MAXSIZE;
-    iov[k].iov_len = UV__UDP_DGRAM_MAXSIZE;
-    msgs[k].msg_hdr.msg_iov = iov + k;
-    msgs[k].msg_hdr.msg_iovlen = 1;
-    msgs[k].msg_hdr.msg_name = peers + k;
-    msgs[k].msg_hdr.msg_namelen = sizeof(peers[0]);
-  }
-
-  do
-    nread = uv__recvmmsg(handle->io_watcher.fd, msgs, chunks, 0, NULL);
-  while (nread == -1 && errno == EINTR);
-
-  if (nread < 1) {
-    if (nread == 0 || errno == EAGAIN || errno == EWOULDBLOCK)
-      handle->recv_cb(handle, 0, buf, NULL, 0);
-    else
-      handle->recv_cb(handle, UV__ERR(errno), buf, NULL, 0);
-  } else {
-    /* pass each chunk to the application */
-    for (k = 0; k < (size_t) nread && handle->recv_cb != NULL; k++) {
-      flags = UV_UDP_MMSG_CHUNK;
-      if (msgs[k].msg_hdr.msg_flags & MSG_TRUNC)
-        flags |= UV_UDP_PARTIAL;
-
-      chunk_buf = uv_buf_init(iov[k].iov_base, iov[k].iov_len);
-      handle->recv_cb(handle,
-                      msgs[k].msg_len,
-                      &chunk_buf,
-                      msgs[k].msg_hdr.msg_name,
-                      flags);
-    }
-
-    /* one last callback so the original buffer is freed */
-    if (handle->recv_cb != NULL)
-      handle->recv_cb(handle, 0, buf, NULL, 0);
-  }
-  return nread;
-}
-#endif
 
 static void uv__udp_recvmsg(uv_udp_t* handle) {
   struct sockaddr_storage peer;
@@ -254,27 +167,13 @@ static void uv__udp_recvmsg(uv_udp_t* handle) {
 
   do {
     buf = uv_buf_init(NULL, 0);
-    handle->alloc_cb((uv_handle_t*) handle, UV__UDP_DGRAM_MAXSIZE, &buf);
+    handle->alloc_cb((uv_handle_t*) handle, 64 * 1024, &buf);
     if (buf.base == NULL || buf.len == 0) {
       handle->recv_cb(handle, UV_ENOBUFS, &buf, NULL, 0);
       return;
     }
     assert(buf.base != NULL);
 
-#if HAVE_MMSG
-    uv_once(&once, uv__udp_mmsg_init);
-    if (uv__recvmmsg_avail) {
-      /* Returned space for more than 1 datagram, use it to receive
-       * multiple datagrams. */
-      if (buf.len >= 2 * UV__UDP_DGRAM_MAXSIZE) {
-        nread = uv__udp_recvmmsg(handle, &buf);
-        if (nread > 0)
-          count -= nread;
-        continue;
-      }
-    }
-#endif
-
     memset(&h, 0, sizeof(h));
     memset(&peer, 0, sizeof(peer));
     h.msg_name = &peer;
@@ -300,120 +199,21 @@ static void uv__udp_recvmsg(uv_udp_t* handle) {
 
       handle->recv_cb(handle, nread, &buf, (const struct sockaddr*) &peer, flags);
     }
-    count--;
   }
   /* recv_cb callback may decide to pause or close the handle */
   while (nread != -1
-      && count > 0
+      && count-- > 0
       && handle->io_watcher.fd != -1
       && handle->recv_cb != NULL);
 }
 
-#if HAVE_MMSG
-static void uv__udp_sendmmsg(uv_udp_t* handle) {
-  uv_udp_send_t* req;
-  struct uv__mmsghdr h[UV__MMSG_MAXWIDTH];
-  struct uv__mmsghdr *p;
-  QUEUE* q;
-  ssize_t npkts;
-  size_t pkts;
-  size_t i;
-
-  if (QUEUE_EMPTY(&handle->write_queue))
-    return;
-
-write_queue_drain:
-  for (pkts = 0, q = QUEUE_HEAD(&handle->write_queue);
-       pkts < UV__MMSG_MAXWIDTH && q != &handle->write_queue;
-       ++pkts, q = QUEUE_HEAD(q)) {
-    assert(q != NULL);
-    req = QUEUE_DATA(q, uv_udp_send_t, queue);
-    assert(req != NULL);
-
-    p = &h[pkts];
-    memset(p, 0, sizeof(*p));
-    if (req->addr.ss_family == AF_UNSPEC) {
-      p->msg_hdr.msg_name = NULL;
-      p->msg_hdr.msg_namelen = 0;
-    } else {
-      p->msg_hdr.msg_name = &req->addr;
-      if (req->addr.ss_family == AF_INET6)
-        p->msg_hdr.msg_namelen = sizeof(struct sockaddr_in6);
-      else if (req->addr.ss_family == AF_INET)
-        p->msg_hdr.msg_namelen = sizeof(struct sockaddr_in);
-      else if (req->addr.ss_family == AF_UNIX)
-        p->msg_hdr.msg_namelen = sizeof(struct sockaddr_un);
-      else {
-        assert(0 && "unsupported address family");
-        abort();
-      }
-    }
-    h[pkts].msg_hdr.msg_iov = (struct iovec*) req->bufs;
-    h[pkts].msg_hdr.msg_iovlen = req->nbufs;
-  }
-
-  do
-    npkts = uv__sendmmsg(handle->io_watcher.fd, h, pkts, 0);
-  while (npkts == -1 && errno == EINTR);
-
-  if (npkts < 1) {
-    if (errno == EAGAIN || errno == EWOULDBLOCK || errno == ENOBUFS)
-      return;
-    for (i = 0, q = QUEUE_HEAD(&handle->write_queue);
-         i < pkts && q != &handle->write_queue;
-         ++i, q = QUEUE_HEAD(q)) {
-      assert(q != NULL);
-      req = QUEUE_DATA(q, uv_udp_send_t, queue);
-      assert(req != NULL);
-
-      req->status = UV__ERR(errno);
-      QUEUE_REMOVE(&req->queue);
-      QUEUE_INSERT_TAIL(&handle->write_completed_queue, &req->queue);
-    }
-    uv__io_feed(handle->loop, &handle->io_watcher);
-    return;
-  }
-
-  for (i = 0, q = QUEUE_HEAD(&handle->write_queue);
-       i < pkts && q != &handle->write_queue;
-       ++i, q = QUEUE_HEAD(&handle->write_queue)) {
-    assert(q != NULL);
-    req = QUEUE_DATA(q, uv_udp_send_t, queue);
-    assert(req != NULL);
-
-    req->status = req->bufs[0].len;
-
-    /* Sending a datagram is an atomic operation: either all data
-     * is written or nothing is (and EMSGSIZE is raised). That is
-     * why we don't handle partial writes. Just pop the request
-     * off the write queue and onto the completed queue, done.
-     */
-    QUEUE_REMOVE(&req->queue);
-    QUEUE_INSERT_TAIL(&handle->write_completed_queue, &req->queue);
-  }
-
-  /* couldn't batch everything, continue sending (jump to avoid stack growth) */
-  if (!QUEUE_EMPTY(&handle->write_queue))
-    goto write_queue_drain;
-  uv__io_feed(handle->loop, &handle->io_watcher);
-  return;
-}
-#endif
 
 static void uv__udp_sendmsg(uv_udp_t* handle) {
   uv_udp_send_t* req;
-  struct msghdr h;
   QUEUE* q;
+  struct msghdr h;
   ssize_t size;
 
-#if HAVE_MMSG
-  uv_once(&once, uv__udp_mmsg_init);
-  if (uv__sendmmsg_avail) {
-    uv__udp_sendmmsg(handle);
-    return;
-  }
-#endif
-
   while (!QUEUE_EMPTY(&handle->write_queue)) {
     q = QUEUE_HEAD(&handle->write_queue);
     assert(q != NULL);
@@ -463,6 +263,7 @@ static void uv__udp_sendmsg(uv_udp_t* handle) {
   }
 }
 
+
 /* On the BSDs, SO_REUSEPORT implies SO_REUSEADDR but with some additional
  * refinements for programs that use multicast.
  *