[PATCH net-next] fou: Support binding FoU socket

* [PATCH net-next] fou: Support binding FoU socket
@ 2019-03-20  8:25 Kristian Evensen
  2019-03-21 18:30 ` kbuild test robot
  2019-03-21 20:10 ` David Miller
  0 siblings, 2 replies; 5+ messages in thread
From: Kristian Evensen @ 2019-03-20  8:25 UTC (permalink / raw)
  To: netdev; +Cc: Kristian Evensen

An FoU socket is currently bound to the wildcard-address. While this
works fine, there are several use-cases where the use of the
wildcard-address is not desirable. For example, I use FoU on some
multi-homed servers and would like to use FoU on only one of the
interfaces.

This commit adds support for binding FoU sockets to a given source
address/interface, as well as connecting the socket to a given
destination address/port. udp_tunnel already provides the required
infrastructure, so most of the code added is for exposing and setting
the different attributes (local address, peer address, etc.).

The lookups performed when we add, delete or get an FoU-socket has also
been updated to compare all the attributes a user can set. Since the
comparison now involves several elements, I have added a separate
comparison-function instead of open-coding.

I have been running this code for a while on some servers I am
responsible for, and I have not found any regressions. If none of the
new attributes are provided, then an FoU-socket is configured as before.
If any of the new attributes are provided, the FoU-socket is configured
as expected.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
---
 include/uapi/linux/fou.h |   6 ++
 net/ipv4/fou.c           | 121 +++++++++++++++++++++++++++++++++------
 2 files changed, 111 insertions(+), 16 deletions(-)

diff --git a/include/uapi/linux/fou.h b/include/uapi/linux/fou.h
index f2ea833a2812..87c2c9f08803 100644
--- a/include/uapi/linux/fou.h
+++ b/include/uapi/linux/fou.h
@@ -16,6 +16,12 @@ enum {
 	FOU_ATTR_IPPROTO,			/* u8 */
 	FOU_ATTR_TYPE,				/* u8 */
 	FOU_ATTR_REMCSUM_NOPARTIAL,		/* flag */
+	FOU_ATTR_LOCAL_V4,			/* u32 */
+	FOU_ATTR_LOCAL_V6,			/* in6_addr */
+	FOU_ATTR_PEER_V4,			/* u32 */
+	FOU_ATTR_PEER_V6,			/* in6_addr */
+	FOU_ATTR_PEER_PORT,			/* u16 */
+	FOU_ATTR_IFINDEX,			/* s32 */
 
 	__FOU_ATTR_MAX,
 };
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 79e98e21cdd7..f8c655f407b2 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -499,15 +499,32 @@ static int gue_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
 	return err;
 }
 
-static int fou_add_to_port_list(struct net *net, struct fou *fou)
+static bool fou_cfg_cmp(struct fou *fou, struct fou_cfg *cfg)
+{
+	struct sock *sk = fou->sock->sk;
+	struct udp_port_cfg *udp_cfg = &cfg->udp_config;
+
+	return fou->family == udp_cfg->family &&
+	       fou->port == udp_cfg->local_udp_port &&
+	       sk->sk_dport == udp_cfg->peer_udp_port &&
+	       sk->sk_bound_dev_if == udp_cfg->bind_ifindex &&
+	       ((fou->family == AF_INET &&
+		 sk->sk_rcv_saddr == udp_cfg->local_ip.s_addr &&
+		 sk->sk_daddr == udp_cfg->peer_ip.s_addr) ||
+		(fou->family == AF_INET6 &&
+		 !ipv6_addr_cmp(&sk->sk_v6_rcv_saddr, &udp_cfg->local_ip6) &&
+		 !ipv6_addr_cmp(&sk->sk_v6_daddr, &udp_cfg->peer_ip6)));
+}
+
+static int fou_add_to_port_list(struct net *net, struct fou *fou,
+				struct fou_cfg *cfg)
 {
 	struct fou_net *fn = net_generic(net, fou_net_id);
 	struct fou *fout;
 
 	mutex_lock(&fn->fou_lock);
 	list_for_each_entry(fout, &fn->fou_list, list) {
-		if (fou->port == fout->port &&
-		    fou->family == fout->family) {
+		if (fou_cfg_cmp(fout, cfg)) {
 			mutex_unlock(&fn->fou_lock);
 			return -EALREADY;
 		}
@@ -585,7 +602,7 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 
 	sk->sk_allocation = GFP_ATOMIC;
 
-	err = fou_add_to_port_list(net, fou);
+	err = fou_add_to_port_list(net, fou, cfg);
 	if (err)
 		goto error;
 
@@ -605,14 +622,12 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 static int fou_destroy(struct net *net, struct fou_cfg *cfg)
 {
 	struct fou_net *fn = net_generic(net, fou_net_id);
-	__be16 port = cfg->udp_config.local_udp_port;
-	u8 family = cfg->udp_config.family;
 	int err = -EINVAL;
 	struct fou *fou;
 
 	mutex_lock(&fn->fou_lock);
 	list_for_each_entry(fou, &fn->fou_list, list) {
-		if (fou->port == port && fou->family == family) {
+		if (fou_cfg_cmp(fou, cfg)) {
 			fou_release(fou);
 			err = 0;
 			break;
@@ -626,16 +641,26 @@ static int fou_destroy(struct net *net, struct fou_cfg *cfg)
 static struct genl_family fou_nl_family;
 
 static const struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
-	[FOU_ATTR_PORT] = { .type = NLA_U16, },
-	[FOU_ATTR_AF] = { .type = NLA_U8, },
-	[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
-	[FOU_ATTR_TYPE] = { .type = NLA_U8, },
-	[FOU_ATTR_REMCSUM_NOPARTIAL] = { .type = NLA_FLAG, },
+	[FOU_ATTR_PORT]			= { .type = NLA_U16, },
+	[FOU_ATTR_AF]			= { .type = NLA_U8, },
+	[FOU_ATTR_IPPROTO]		= { .type = NLA_U8, },
+	[FOU_ATTR_TYPE]			= { .type = NLA_U8, },
+	[FOU_ATTR_REMCSUM_NOPARTIAL]	= { .type = NLA_FLAG, },
+	[FOU_ATTR_LOCAL_V4]		= { .type = NLA_U32, },
+	[FOU_ATTR_PEER_V4]		= { .type = NLA_U32, },
+	[FOU_ATTR_LOCAL_V6]		= { .type = sizeof(struct in6_addr), },
+	[FOU_ATTR_PEER_V6]		= { .type = sizeof(struct in6_addr), },
+	[FOU_ATTR_PEER_PORT]		= { .type = NLA_U16, },
+	[FOU_ATTR_IFINDEX]		= { .type = NLA_S32, },
 };
 
 static int parse_nl_config(struct genl_info *info,
 			   struct fou_cfg *cfg)
 {
+	bool has_local = false, has_peer = false;
+	struct nlattr *attr;
+	__be16 port;
+
 	memset(cfg, 0, sizeof(*cfg));
 
 	cfg->udp_config.family = AF_INET;
@@ -657,8 +682,7 @@ static int parse_nl_config(struct genl_info *info,
 	}
 
 	if (info->attrs[FOU_ATTR_PORT]) {
-		__be16 port = nla_get_be16(info->attrs[FOU_ATTR_PORT]);
-
+		port = nla_get_be16(info->attrs[FOU_ATTR_PORT]);
 		cfg->udp_config.local_udp_port = port;
 	}
 
@@ -671,6 +695,51 @@ static int parse_nl_config(struct genl_info *info,
 	if (info->attrs[FOU_ATTR_REMCSUM_NOPARTIAL])
 		cfg->flags |= FOU_F_REMCSUM_NOPARTIAL;
 
+	if (cfg->udp_config.family == AF_INET) {
+		if (info->attrs[FOU_ATTR_LOCAL_V4]) {
+			attr = info->attrs[FOU_ATTR_LOCAL_V4];
+			cfg->udp_config.local_ip.s_addr = nla_get_in_addr(attr);
+			has_local = true;
+		}
+
+		if (info->attrs[FOU_ATTR_PEER_V4]) {
+			attr = info->attrs[FOU_ATTR_PEER_V4];
+			cfg->udp_config.peer_ip.s_addr = nla_get_in_addr(attr);
+			has_peer = true;
+		}
+	} else {
+		if (info->attrs[FOU_ATTR_LOCAL_V6]) {
+			attr = info->attrs[FOU_ATTR_LOCAL_V6];
+			cfg->udp_config.local_ip6 = nla_get_in6_addr(attr);
+			has_local = true;
+		}
+
+		if (info->attrs[FOU_ATTR_PEER_V6]) {
+			attr = info->attrs[FOU_ATTR_PEER_V6];
+			cfg->udp_config.peer_ip6 = nla_get_in6_addr(attr);
+			has_peer = true;
+		}
+	}
+
+	if (info->attrs[FOU_ATTR_PEER_PORT]) {
+		if (!has_peer)
+			return -EINVAL;
+
+		port = nla_get_be16(info->attrs[FOU_ATTR_PEER_PORT]);
+		cfg->udp_config.peer_udp_port = port;
+	}
+
+	if (info->attrs[FOU_ATTR_IFINDEX]) {
+		int ifindex;
+
+		if (!has_local)
+			return -EINVAL;
+
+		ifindex = nla_get_s32(info->attrs[FOU_ATTR_IFINDEX]);
+
+		cfg->udp_config.bind_ifindex = ifindex;
+	}
+
 	return 0;
 }
 
@@ -702,15 +771,35 @@ static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info)
 
 static int fou_fill_info(struct fou *fou, struct sk_buff *msg)
 {
+	struct sock *sk = fou->sock->sk;
+
 	if (nla_put_u8(msg, FOU_ATTR_AF, fou->sock->sk->sk_family) ||
 	    nla_put_be16(msg, FOU_ATTR_PORT, fou->port) ||
+	    nla_put_be16(msg, FOU_ATTR_PEER_PORT, sk->sk_dport) ||
 	    nla_put_u8(msg, FOU_ATTR_IPPROTO, fou->protocol) ||
-	    nla_put_u8(msg, FOU_ATTR_TYPE, fou->type))
+	    nla_put_u8(msg, FOU_ATTR_TYPE, fou->type) ||
+	    nla_put_s32(msg, FOU_ATTR_IFINDEX, sk->sk_bound_dev_if))
 		return -1;
 
 	if (fou->flags & FOU_F_REMCSUM_NOPARTIAL)
 		if (nla_put_flag(msg, FOU_ATTR_REMCSUM_NOPARTIAL))
 			return -1;
+
+	if (fou->sock->sk->sk_family == AF_INET) {
+		if (nla_put_in_addr(msg, FOU_ATTR_LOCAL_V4, sk->sk_rcv_saddr))
+			return -1;
+
+		if (nla_put_in_addr(msg, FOU_ATTR_PEER_V4, sk->sk_daddr))
+			return -1;
+	} else {
+		if (nla_put_in6_addr(msg, FOU_ATTR_LOCAL_V6,
+				     &sk->sk_v6_rcv_saddr))
+			return -1;
+
+		if (nla_put_in6_addr(msg, FOU_ATTR_PEER_V6, &sk->sk_v6_daddr))
+			return -1;
+	}
+
 	return 0;
 }
 
@@ -763,7 +852,7 @@ static int fou_nl_cmd_get_port(struct sk_buff *skb, struct genl_info *info)
 	ret = -ESRCH;
 	mutex_lock(&fn->fou_lock);
 	list_for_each_entry(fout, &fn->fou_list, list) {
-		if (port == fout->port && family == fout->family) {
+		if (fou_cfg_cmp(fout, &cfg)) {
 			ret = fou_dump_info(fout, info->snd_portid,
 					    info->snd_seq, 0, msg,
 					    info->genlhdr->cmd);
-- 
2.19.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread