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Message-Id: <1328551064-28573-1-git-send-email-ehoover@mines.edu>
Date: Mon, 6 Feb 2012 10:57:43 -0700
From: "Erich E. Hoover" <ehoover@...es.edu>
To: Linux Netdev <netdev@...r.kernel.org>
Cc: "Erich E. Hoover" <ehoover@...es.edu>
Subject: [PATCH v3 1/2] Implement IP_UNICAST_IF socket option.
The IP_UNICAST_IF feature is needed by the Wine project. This patch implements the feature by setting the outgoing interface in a similar fashion to that of IP_PKTINFO. A separate option is needed to handle this feature since the existing options do not provide all of the characteristics required by IP_UNICAST_IF, a summary is provided below.
SO_BINDTODEVICE:
* SO_BINDTODEVICE requires administrative privileges, IP_UNICAST_IF does not. From reading some old mailing list articles my understanding is that SO_BINDTODEVICE requires administrative privileges because it can override the administrator's routing settings.
* The SO_BINDTODEVICE option restricts both outbound and inbound traffic, IP_UNICAST_IF only impacts outbound traffic.
IP_PKTINFO:
* Since IP_PKTINFO and IP_UNICAST_IF are independent options, implementing IP_UNICAST_IF with IP_PKTINFO will likely break some applications.
* Implementing IP_UNICAST_IF on top of IP_PKTINFO significantly complicates the Wine codebase and reduces the socket performance (doing this requires a lot of extra communication between the "server" and "user" layers).
bind():
* bind() does not work on broadcast packets, IP_UNICAST_IF is specifically intended to work with broadcast packets.
Signed-off-by: Erich E. Hoover <ehoover@...es.edu>
---
include/linux/in.h | 1 +
include/net/inet_sock.h | 2 +
include/net/ip.h | 1 +
net/ipv4/af_inet.c | 2 +
net/ipv4/ip_sockglue.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
net/ipv4/ping.c | 2 +-
net/ipv4/raw.c | 2 +-
net/ipv4/udp.c | 2 +-
net/ipv6/af_inet6.c | 2 +
9 files changed, 59 insertions(+), 3 deletions(-)
diff --git a/include/linux/in.h b/include/linux/in.h
index 01129c0..89f6682 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -86,6 +86,7 @@ struct in_addr {
#define IP_MINTTL 21
#define IP_NODEFRAG 22
+#define IP_UNICAST_IF 23
/* IP_MTU_DISCOVER values */
#define IP_PMTUDISC_DONT 0 /* Never send DF frames */
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index e3e4051..ad517f5 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -132,6 +132,7 @@ struct rtable;
* @tos - TOS
* @mc_ttl - Multicasting TTL
* @is_icsk - is this an inet_connection_sock?
+ * @outif_index - Outgoing device index
* @mc_index - Multicast device index
* @mc_list - Group array
* @cork - info to build ip hdr on each ip frag while socket is corked
@@ -167,6 +168,7 @@ struct inet_sock {
transparent:1,
mc_all:1,
nodefrag:1;
+ int outif_index;
int mc_index;
__be32 mc_addr;
struct ip_mc_socklist __rcu *mc_list;
diff --git a/include/net/ip.h b/include/net/ip.h
index 775009f..05aa269 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -452,6 +452,7 @@ extern int ip_options_rcv_srr(struct sk_buff *skb);
extern void ipv4_pktinfo_prepare(struct sk_buff *skb);
extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
+extern int ip_default_ifindex(const struct sock *sk);
extern int ip_cmsg_send(struct net *net,
struct msghdr *msg, struct ipcm_cookie *ipc);
extern int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index f7b5670..a5855cd 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -375,6 +375,8 @@ lookup_protocol:
sk->sk_protocol = protocol;
sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
+ inet->outif_index = 0;
+
inet->uc_ttl = -1;
inet->mc_loop = 1;
inet->mc_ttl = 1;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 8aa87c1..87646e4 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -186,6 +186,21 @@ void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
}
EXPORT_SYMBOL(ip_cmsg_recv);
+int ip_default_ifindex(const struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ int ifindex = sk->sk_bound_dev_if;
+
+ /*
+ * If not bound to a specific interface then set the outgoing interface
+ * to the value from the IP_UNICAST_IF socket option.
+ */
+ if (!ifindex)
+ ifindex = inet->outif_index;
+
+ return ifindex;
+}
+
int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc)
{
int err;
@@ -469,6 +484,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
(1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) |
(1<<IP_PASSSEC) | (1<<IP_TRANSPARENT) |
(1<<IP_MINTTL) | (1<<IP_NODEFRAG))) ||
+ optname == IP_UNICAST_IF ||
optname == IP_MULTICAST_TTL ||
optname == IP_MULTICAST_ALL ||
optname == IP_MULTICAST_LOOP ||
@@ -628,6 +644,35 @@ static int do_ip_setsockopt(struct sock *sk, int level,
goto e_inval;
inet->mc_loop = !!val;
break;
+ case IP_UNICAST_IF:
+ {
+ struct net_device *dev = NULL;
+ int ifindex;
+
+ if (optlen != sizeof(int))
+ goto e_inval;
+
+ ifindex = (__force int)ntohl((__force __be32)val);
+ if (ifindex == 0) {
+ inet->outif_index = 0;
+ err = 0;
+ break;
+ }
+
+ dev = dev_get_by_index(sock_net(sk), ifindex);
+ err = -EADDRNOTAVAIL;
+ if (!dev)
+ break;
+ dev_put(dev);
+
+ err = -EINVAL;
+ if (sk->sk_bound_dev_if && ifindex != sk->sk_bound_dev_if)
+ break;
+
+ inet->outif_index = ifindex;
+ err = 0;
+ break;
+ }
case IP_MULTICAST_IF:
{
struct ip_mreqn mreq;
@@ -1178,6 +1223,9 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_MULTICAST_LOOP:
val = inet->mc_loop;
break;
+ case IP_UNICAST_IF:
+ val = (__force int)htonl((__u32) inet->outif_index);
+ break;
case IP_MULTICAST_IF:
{
struct in_addr addr;
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index aea5a19..abeb454 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -510,7 +510,7 @@ static int ping_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
ipc.addr = inet->inet_saddr;
ipc.opt = NULL;
- ipc.oif = sk->sk_bound_dev_if;
+ ipc.oif = ip_default_ifindex(sk);
ipc.tx_flags = 0;
err = sock_tx_timestamp(sk, &ipc.tx_flags);
if (err)
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 3ccda5a..000d9fb 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -515,7 +515,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
ipc.addr = inet->inet_saddr;
ipc.opt = NULL;
ipc.tx_flags = 0;
- ipc.oif = sk->sk_bound_dev_if;
+ ipc.oif = ip_default_ifindex(sk);
if (msg->msg_controllen) {
err = ip_cmsg_send(sock_net(sk), msg, &ipc);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5d075b5..651eb62 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -869,7 +869,7 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
}
ipc.addr = inet->inet_saddr;
- ipc.oif = sk->sk_bound_dev_if;
+ ipc.oif = ip_default_ifindex(sk);
err = sock_tx_timestamp(sk, &ipc.tx_flags);
if (err)
return err;
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 273f48d..13b84bc 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -210,6 +210,8 @@ lookup_protocol:
*/
inet->uc_ttl = -1;
+ inet->outif_index = 0;
+
inet->mc_loop = 1;
inet->mc_ttl = 1;
inet->mc_index = 0;
--
1.7.5.4
--
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