ipv4: processing ancillary IP_TOS or IP_TTL
If IP_TOS or IP_TTL are specified as ancillary data, then sendmsg() sends out
packets with the specified TTL or TOS overriding the socket values specified
with the traditional setsockopt().
The struct inet_cork stores the values of TOS, TTL and priority that are
passed through the struct ipcm_cookie. If there are user-specified TOS
(tos != -1) or TTL (ttl != 0) in the struct ipcm_cookie, these values are
used to override the per-socket values. In case of TOS also the priority
is changed accordingly.
Two helper functions get_rttos and get_rtconn_flags are defined to take
into account the presence of a user specified TOS value when computing
RT_TOS and RT_CONN_FLAGS.
Signed-off-by: Francesco Fusco <ffusco@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index a04d872..7d8357b 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1060,6 +1060,9 @@
rt->dst.dev->mtu : dst_mtu(&rt->dst);
cork->dst = &rt->dst;
cork->length = 0;
+ cork->ttl = ipc->ttl;
+ cork->tos = ipc->tos;
+ cork->priority = ipc->priority;
cork->tx_flags = ipc->tx_flags;
return 0;
@@ -1311,7 +1314,9 @@
if (cork->flags & IPCORK_OPT)
opt = cork->opt;
- if (rt->rt_type == RTN_MULTICAST)
+ if (cork->ttl != 0)
+ ttl = cork->ttl;
+ else if (rt->rt_type == RTN_MULTICAST)
ttl = inet->mc_ttl;
else
ttl = ip_select_ttl(inet, &rt->dst);
@@ -1319,7 +1324,7 @@
iph = ip_hdr(skb);
iph->version = 4;
iph->ihl = 5;
- iph->tos = inet->tos;
+ iph->tos = (cork->tos != -1) ? cork->tos : inet->tos;
iph->frag_off = df;
iph->ttl = ttl;
iph->protocol = sk->sk_protocol;
@@ -1331,7 +1336,7 @@
ip_options_build(skb, opt, cork->addr, rt, 0);
}
- skb->priority = sk->sk_priority;
+ skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority;
skb->mark = sk->sk_mark;
/*
* Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
@@ -1481,6 +1486,8 @@
ipc.addr = daddr;
ipc.opt = NULL;
ipc.tx_flags = 0;
+ ipc.ttl = 0;
+ ipc.tos = -1;
if (replyopts.opt.opt.optlen) {
ipc.opt = &replyopts.opt;