126 lines
4.0 KiB
Diff
126 lines
4.0 KiB
Diff
From 3b4ca6b87dae6b11da137b6afb4cf8275687d281 Mon Sep 17 00:00:00 2001
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From: Chris Leech <cleech@redhat.com>
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Date: Thu, 24 Jan 2019 18:16:47 -0800
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Subject: [PATCH] fcoemon: netlink buffer resize fix
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The recv buffer resizing for netlink messages looks to have always been
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busted, it discards some of the data in the process of increasing the
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buffer size.
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I've recently seen issues where the size of the netlink attributes in a
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GETLINK request hit the fcm_link_buf_size window and some of the network
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interfaces were ignored by fcoemon (happened mostly with recent kernels,
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2 dual-port bnx2 NICs, bonding for LAN traffic on 2 ports and FCoE on
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the other 2). When the ignored interface happens to be the one you want
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to use for FCoE, it never gets fixed.
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This fixes the buffer resize code to use MSG_PEEK|MSG_TRUNC to check for
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the needed buffer size first, and then resize with realloc when needed.
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This might not actually be needed, with an 8k buffer I don't think the
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kernel side will send more at once until after it sees the application
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post a larger buffer, but I did force a resize and see that it worked.
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Signed-off-by: Chris Leech <cleech@redhat.com>
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---
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fcoemon.c | 54 ++++++++++++++++++------------------------------------
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1 file changed, 18 insertions(+), 36 deletions(-)
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diff --git a/fcoemon.c b/fcoemon.c
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index 9a400c56b72..9af0f1284af 100644
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--- a/fcoemon.c
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+++ b/fcoemon.c
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@@ -328,7 +328,6 @@ static int fcm_link_socket;
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static int fcm_link_seq;
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static void fcm_link_recv(void *);
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static void fcm_link_getlink(void);
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-static int fcm_link_buf_check(size_t);
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static void clear_dcbd_info(struct fcm_netif *ff);
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static int fcoe_vid_from_ifname(const char *ifname);
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@@ -354,8 +353,7 @@ char progname[20];
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* large enough to fit and expand it if we ever do a read that almost fills it.
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*/
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static char *fcm_link_buf;
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-static size_t fcm_link_buf_size = 4096; /* initial size */
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-static const size_t fcm_link_buf_fuzz = 300; /* "almost full" remainder */
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+static size_t fcm_link_buf_size = 8192; /* initial size */
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/*
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* A value must be surrounded by quates, e.g. "x".
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@@ -1848,8 +1846,22 @@ static void fcm_link_recv(UNUSED void *arg)
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size_t plen;
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size_t rlen;
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+ /* check to make sure our receive buffer is large enough,
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+ * or scale it up as needed */
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+ rc = recv(fcm_link_socket, NULL, 0, MSG_PEEK | MSG_TRUNC);
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+ if (rc > fcm_link_buf_size) {
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+ FCM_LOG_DBG("resizing link buf to %d bytes\n", rc);
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+ void *resize = realloc(fcm_link_buf, rc);
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+ if (resize) {
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+ fcm_link_buf = resize;
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+ fcm_link_buf_size = rc;
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+ } else {
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+ FCM_LOG_ERR(errno, "Failed to allocate link buffer");
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+ }
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+ }
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+
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buf = fcm_link_buf;
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- rc = read(fcm_link_socket, buf, fcm_link_buf_size);
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+ rc = recv(fcm_link_socket, buf, fcm_link_buf_size, 0);
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if (rc <= 0) {
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if (rc < 0)
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FCM_LOG_ERR(errno, "Error reading from "
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@@ -1858,11 +1870,6 @@ static void fcm_link_recv(UNUSED void *arg)
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return;
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}
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- if (fcm_link_buf_check(rc)) {
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- fcm_link_getlink();
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- return;
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- }
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-
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hp = (struct nlmsghdr *)buf;
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rlen = rc;
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for (hp = (struct nlmsghdr *)buf; NLMSG_OK(hp, rlen);
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@@ -1927,34 +1934,9 @@ static void fcm_link_getlink(void)
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msg.nl.nlmsg_pid = getpid();
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msg.ifi.ifi_family = AF_UNSPEC;
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msg.ifi.ifi_type = ARPHRD_ETHER;
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- rc = write(fcm_link_socket, &msg, sizeof(msg));
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+ rc = send(fcm_link_socket, &msg, sizeof(msg), 0);
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if (rc < 0)
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- FCM_LOG_ERR(errno, "write error");
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-}
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-
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-/*
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- * Check for whether buffer needs to grow based on amount read.
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- * Free's the old buffer so don't use that after this returns non-zero.
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- */
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-static int fcm_link_buf_check(size_t read_len)
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-{
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- char *buf;
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- size_t len = read_len;
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-
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- if (len > fcm_link_buf_size - fcm_link_buf_fuzz) {
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- len = fcm_link_buf_size;
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- len = len + len / 2; /* grow by 50% */
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- buf = malloc(len);
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- if (buf != NULL) {
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- free(fcm_link_buf);
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- fcm_link_buf = buf;
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- fcm_link_buf_size = len;
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- return 1;
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- } else {
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- FCM_LOG_ERR(errno, "failed to allocate link buffer");
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- }
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- }
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- return 0;
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+ FCM_LOG_ERR(errno, "send error");
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}
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static void fcm_fcoe_init(void)
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--
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2.21.0
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