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93 lines
2.9 KiB
93 lines
2.9 KiB
6 years ago
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From 61ccf0f453306e727e254e6de1641bb934a3b7ec Mon Sep 17 00:00:00 2001
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From: Hangbin Liu <haliu@redhat.com>
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Date: Wed, 8 Nov 2017 14:39:07 +0800
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Subject: [PATCH] netlink: Change rtnl_dump_done to always show error
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1380803
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Upstream Status: iproute2.git commit 05a14fc12188
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commit 05a14fc1218885ba6236b409fbf6b89976b8636e
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Author: David Ahern <dsahern@gmail.com>
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Date: Tue May 16 14:22:46 2017 -0700
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netlink: Change rtnl_dump_done to always show error
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The original code which became rtnl_dump_done only shows netlink errors
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if the protocol is NETLINK_SOCK_DIAG, but netlink dumps always appends
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the length which contains any error encountered during the dump. Update
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rtnl_dump_done to always show the error if there is one.
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As an *example* without this patch, dumping a route object that exceeds
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the internal buffer size terminates with no message to the user -- the
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dump just ends because the NLMSG_DONE attribute was received. With this
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patch the user at least gets a message that the dump was aborted.
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$ ip ro ls
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default via 10.0.2.2 dev eth0
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10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15
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10.10.0.0/16 dev veth1 proto kernel scope link src 10.10.0.1
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172.16.1.0/24 dev br0.11 proto kernel scope link src 172.16.1.1
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Error: Buffer too small for object
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Dump terminated
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The point of this patch is to notify the user of a failure versus
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silently exiting on a partial dump. Because the NLMSG_DONE attribute
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was received, the entire dump needs to be restarted to use a larger
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buffer for EMSGSIZE errors. That could be done automatically but it
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has other user impacts (e.g., duplicate output if the dump is
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restarted) and should be the subject of a different patch.
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Signed-off-by: David Ahern <dsahern@gmail.com>
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Signed-off-by: Hangbin Liu <haliu@redhat.com>
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---
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lib/libnetlink.c | 28 +++++++++++++++++-----------
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1 file changed, 17 insertions(+), 11 deletions(-)
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diff --git a/lib/libnetlink.c b/lib/libnetlink.c
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index 9303b66..e91bd5a 100644
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--- a/lib/libnetlink.c
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+++ b/lib/libnetlink.c
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@@ -266,21 +266,27 @@ static int rtnl_dump_done(const struct rtnl_handle *rth,
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{
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int len = *(int *)NLMSG_DATA(h);
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- if (rth->proto == NETLINK_SOCK_DIAG) {
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- if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) {
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- fprintf(stderr, "DONE truncated\n");
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- return -1;
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- }
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-
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+ if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) {
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+ fprintf(stderr, "DONE truncated\n");
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+ return -1;
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+ }
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- if (len < 0) {
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- errno = -len;
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- if (errno == ENOENT || errno == EOPNOTSUPP)
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- return -1;
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+ if (len < 0) {
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+ errno = -len;
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+ switch (errno) {
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+ case ENOENT:
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+ case EOPNOTSUPP:
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+ return -1;
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+ case EMSGSIZE:
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+ fprintf(stderr,
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+ "Error: Buffer too small for object.\n");
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+ break;
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+ default:
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perror("RTNETLINK answers");
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- return len;
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}
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+ return len;
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}
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+
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return 0;
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}
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--
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1.8.3.1
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