[PATCH net-next 6/7] tipc: add the ability to get UDP options via netlink

[Richard Alpe <richard.alpe@ericsson.com>]

Add UDP bearer options to netlink bearer get message. This is used by
the tipc user space tool to display UDP options.

The UDP bearer information is passed using either a sockaddr_in or
sockaddr_in6 structs. This means the user space receiver should
intermediately store the retrieved data in a large enough struct
(sockaddr_strage) before casting to the proper IP version type.

Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
---
 include/uapi/linux/tipc_netlink.h |  2 ++
 net/tipc/bearer.c                 |  8 +++++
 net/tipc/udp_media.c              | 61 +++++++++++++++++++++++++++++++++++++++
 net/tipc/udp_media.h              |  1 +
 4 files changed, 72 insertions(+)

diff --git a/include/uapi/linux/tipc_netlink.h b/include/uapi/linux/tipc_netlink.h
index b15664c..f9edd20 100644
--- a/include/uapi/linux/tipc_netlink.h
+++ b/include/uapi/linux/tipc_netlink.h
@@ -61,6 +61,7 @@ enum {
 	TIPC_NL_MON_PEER_GET,
 	TIPC_NL_PEER_REMOVE,
 	TIPC_NL_BEARER_ADD,
+	TIPC_NL_UDP_GET_REMOTEIP,
 
 	__TIPC_NL_CMD_MAX,
 	TIPC_NL_CMD_MAX = __TIPC_NL_CMD_MAX - 1
@@ -100,6 +101,7 @@ enum {
 	TIPC_NLA_UDP_UNSPEC,
 	TIPC_NLA_UDP_LOCAL,		/* sockaddr_storage */
 	TIPC_NLA_UDP_REMOTE,		/* sockaddr_storage */
+	TIPC_NLA_UDP_MULTI_REMOTEIP,	/* flag */
 
 	__TIPC_NLA_UDP_MAX,
 	TIPC_NLA_UDP_MAX = __TIPC_NLA_UDP_MAX - 1
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index d7b442d..975dbeb 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -712,6 +712,14 @@ static int __tipc_nl_add_bearer(struct tipc_nl_msg *msg,
 		goto prop_msg_full;
 
 	nla_nest_end(msg->skb, prop);
+
+#ifdef CONFIG_TIPC_MEDIA_UDP
+	if (bearer->media->type_id == TIPC_MEDIA_TYPE_UDP) {
+		if (tipc_udp_nl_add_bearer_data(msg, bearer))
+			goto attr_msg_full;
+	}
+#endif
+
 	nla_nest_end(msg->skb, attrs);
 	genlmsg_end(msg->skb, hdr);
 
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 6ece3c9..a6cdd98 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -401,6 +401,67 @@ static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
 	return err;
 }
 
+static int __tipc_nl_add_udp_addr(struct sk_buff *skb,
+				  struct udp_media_addr *addr, int nla_t)
+{
+	if (ntohs(addr->proto) == ETH_P_IP) {
+		struct sockaddr_in ip4;
+
+		ip4.sin_family = AF_INET;
+		ip4.sin_port = addr->port;
+		ip4.sin_addr.s_addr = addr->ipv4.s_addr;
+		if (nla_put(skb, nla_t, sizeof(ip4), &ip4))
+			return -EMSGSIZE;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (ntohs(addr->proto) == ETH_P_IPV6) {
+		struct sockaddr_in6 ip6;
+
+		ip6.sin6_family = AF_INET6;
+		ip6.sin6_port  = addr->port;
+		memcpy(&ip6.sin6_addr, &addr->ipv6, sizeof(struct in6_addr));
+		if (nla_put(skb, nla_t, sizeof(ip6), &ip6))
+			return -EMSGSIZE;
+#endif
+	}
+
+	return 0;
+}
+
+int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b)
+{
+	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
+	struct udp_media_addr *dst;
+	struct udp_bearer *ub;
+	struct nlattr *nest;
+
+	ub = rcu_dereference_rtnl(b->media_ptr);
+	if (!ub)
+		return -ENODEV;
+
+	nest = nla_nest_start(msg->skb, TIPC_NLA_BEARER_UDP_OPTS);
+	if (!nest)
+		goto msg_full;
+
+	if (__tipc_nl_add_udp_addr(msg->skb, src, TIPC_NLA_UDP_LOCAL))
+		goto msg_full;
+
+	dst = (struct udp_media_addr *)&b->bcast_addr.value;
+	if (__tipc_nl_add_udp_addr(msg->skb, dst, TIPC_NLA_UDP_REMOTE))
+		goto msg_full;
+
+	if (!list_empty(&ub->rcast.list)) {
+		if (nla_put_flag(msg->skb, TIPC_NLA_UDP_MULTI_REMOTEIP))
+			goto msg_full;
+	}
+
+	nla_nest_end(msg->skb, nest);
+	return 0;
+msg_full:
+	nla_nest_cancel(msg->skb, nest);
+	return -EMSGSIZE;
+}
+
 /**
  * tipc_parse_udp_addr - build udp media address from netlink data
  * @nlattr:	netlink attribute containing sockaddr storage aligned address
diff --git a/net/tipc/udp_media.h b/net/tipc/udp_media.h
index 4dcb548..c06326a 100644
--- a/net/tipc/udp_media.h
+++ b/net/tipc/udp_media.h
@@ -39,6 +39,7 @@
 #define _TIPC_UDP_MEDIA_H
 
 int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr);
+int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b);
 
 #endif
 #endif
-- 
2.1.4


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