libnetlink: Use NLMSG_LENGTH to set nlmsg_len

Change nlmsg_len from sizeof(req) to use NLMSG_LENGTH on the header.
2 of the inner headers are not 4-byte aligned, so add a 0-length buf
after the header with the __aligned(NLMSG_ALIGNTO) to ensure the size
of the request is large enough. Use NLMSG_ALIGN in NLMSG_LENGTH to set
nlmsg_len.

Signed-off-by: David Ahern <dsahern@gmail.com>

diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index e28e1ab6da5e96fa65c9e0b8cc78a62a510f71be..8ab2355fc26b2c0b4547c1a9c233ead73ed49de2 100644 (file)
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -28,6 +28,8 @@
 
 #include "libnetlink.h"
 
+#define __aligned(x)           __attribute__((aligned(x)))
+
 #ifndef SOL_NETLINK
 #define SOL_NETLINK 270
 #endif
@@ -238,7 +240,7 @@ int rtnl_addrdump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct ifaddrmsg ifm;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
                .nlh.nlmsg_type = RTM_GETADDR,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -254,7 +256,7 @@ int rtnl_addrlbldump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct ifaddrlblmsg ifal;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrlblmsg)),
                .nlh.nlmsg_type = RTM_GETADDRLABEL,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -270,7 +272,7 @@ int rtnl_routedump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct rtmsg rtm;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)),
                .nlh.nlmsg_type = RTM_GETROUTE,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -286,7 +288,7 @@ int rtnl_ruledump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct fib_rule_hdr frh;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct fib_rule_hdr)),
                .nlh.nlmsg_type = RTM_GETRULE,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -302,7 +304,7 @@ int rtnl_neighdump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct ndmsg ndm;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ndmsg)),
                .nlh.nlmsg_type = RTM_GETNEIGH,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -318,7 +320,7 @@ int rtnl_neightbldump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct ndtmsg ndtmsg;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ndtmsg)),
                .nlh.nlmsg_type = RTM_GETNEIGHTBL,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -334,7 +336,7 @@ int rtnl_mdbdump_req(struct rtnl_handle *rth, int family)
                struct nlmsghdr nlh;
                struct br_port_msg bpm;
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct br_port_msg)),
                .nlh.nlmsg_type = RTM_GETMDB,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -349,8 +351,9 @@ int rtnl_netconfdump_req(struct rtnl_handle *rth, int family)
        struct {
                struct nlmsghdr nlh;
                struct netconfmsg ncm;
+               char buf[0] __aligned(NLMSG_ALIGNTO);
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct netconfmsg))),
                .nlh.nlmsg_type = RTM_GETNETCONF,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -365,8 +368,9 @@ int rtnl_nsiddump_req(struct rtnl_handle *rth, int family)
        struct {
                struct nlmsghdr nlh;
                struct rtgenmsg rtm;
+               char buf[0] __aligned(NLMSG_ALIGNTO);
        } req = {
-               .nlh.nlmsg_len = sizeof(req),
+               .nlh.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct rtgenmsg))),
                .nlh.nlmsg_type = RTM_GETNSID,
                .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
                .nlh.nlmsg_seq = rth->dump = ++rth->seq,
@@ -388,7 +392,7 @@ int rtnl_linkdump_req_filter(struct rtnl_handle *rth, int family,
                struct nlmsghdr nlh;
                struct ifinfomsg ifm;
                /* attribute has to be NLMSG aligned */
-               struct rtattr ext_req __attribute__ ((aligned(NLMSG_ALIGNTO)));
+               struct rtattr ext_req __aligned(NLMSG_ALIGNTO);
                __u32 ext_filter_mask;
        } req = {
                .nlh.nlmsg_len = sizeof(req),