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Mon, 17 Mar 2025 18:41:22 -0700 (PDT) From: Antonio Quartulli Date: Tue, 18 Mar 2025 02:40:52 +0100 Subject: [PATCH net-next v24 17/23] ovpn: add support for updating local or remote UDP endpoint Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250318-b4-ovpn-v24-17-3ec4ab5c4a77@openvpn.net> References: <20250318-b4-ovpn-v24-0-3ec4ab5c4a77@openvpn.net> In-Reply-To: <20250318-b4-ovpn-v24-0-3ec4ab5c4a77@openvpn.net> To: netdev@vger.kernel.org, Eric Dumazet , Jakub Kicinski , Paolo Abeni , Donald Hunter , Antonio Quartulli , Shuah Khan , sd@queasysnail.net, ryazanov.s.a@gmail.com, Andrew Lunn Cc: Simon Horman , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Xiao Liang X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=9204; i=antonio@openvpn.net; h=from:subject:message-id; bh=0Ct1EXaLi0EA09Bg5/0/MSSXYNAJL46agRawkihgLqw=; b=owEBbQGS/pANAwAIAQtw5TqgONWHAcsmYgBn2M8qSWM855bYhV8AMAGqID3iAM7t8y1kuDat+ qMo8gl7AeyJATMEAAEIAB0WIQSZq9xs+NQS5N5fwPwLcOU6oDjVhwUCZ9jPKgAKCRALcOU6oDjV h8DtB/0cKObFLopkJQ10fsffYbC6JNnAvQU20PmpkXsF4s0W7pZJkofyWfG8xyZoDfS7ovc594/ iAQ3PgNbWG1+nh5I02yEOqfXHNCbpcNGjpuRk3mtXQ5b3KrZRrpPzpJJZtayXJ31RwEiZOPl1iE iNyThLBSaIsBEAK2pZMkGyyB5b+xhQ1InGrptAvFDVcKPnd4djvyjwlMXcE0KglYYZMlCJy695W JU5AaPmh+lsUZxUs+6hQTLkSKSeXsyEf+3o3LWsj/98VUBIeX2Mfs4HFHZT9v1lp2TXl4YqVZye CYWiiETH41TJQb7xBjcU652jAuSOcd6WF0RWmZi6apvAJhA4 X-Developer-Key: i=antonio@openvpn.net; a=openpgp; fpr=CABDA1282017C267219885C748F0CCB68F59D14C In case of UDP links, the local or remote endpoint used to communicate with a given peer may change without a connection restart. Add support for learning the new address in case of change. Signed-off-by: Antonio Quartulli --- drivers/net/ovpn/io.c | 8 ++ drivers/net/ovpn/peer.c | 213 ++++++++++++++++++++++++++++++++++++++++++++= +--- drivers/net/ovpn/peer.h | 2 + 3 files changed, 210 insertions(+), 13 deletions(-) diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c index fcba094ed412068af88cf74baa82ec2742e0b634..49bb58868053e2d1542a8a5849c= 4bbc256083efc 100644 --- a/drivers/net/ovpn/io.c +++ b/drivers/net/ovpn/io.c @@ -96,6 +96,7 @@ void ovpn_decrypt_post(void *data, int ret) struct ovpn_crypto_key_slot *ks; unsigned int payload_offset =3D 0; struct sk_buff *skb =3D data; + struct ovpn_socket *sock; struct ovpn_peer *peer; __be16 proto; __be32 *pid; @@ -137,6 +138,13 @@ void ovpn_decrypt_post(void *data, int ret) /* keep track of last received authenticated packet for keepalive */ WRITE_ONCE(peer->last_recv, ktime_get_real_seconds()); =20 + rcu_read_lock(); + sock =3D rcu_dereference(peer->sock); + if (sock && sock->sock->sk->sk_protocol =3D=3D IPPROTO_UDP) + /* check if this peer changed local or remote endpoint */ + ovpn_peer_endpoints_update(peer, skb); + rcu_read_unlock(); + /* point to encapsulated IP packet */ __skb_pull(skb, payload_offset); =20 diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index 45e87ac155b554044388490a403f64c777d283a6..0d8b12fd5de4cd6fe15455b435c= 7d6807203a825 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -127,6 +127,206 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovp= n, u32 id) return peer; } =20 +/** + * ovpn_peer_reset_sockaddr - recreate binding for peer + * @peer: peer to recreate the binding for + * @ss: sockaddr to use as remote endpoint for the binding + * @local_ip: local IP for the binding + * + * Return: 0 on success or a negative error code otherwise + */ +static int ovpn_peer_reset_sockaddr(struct ovpn_peer *peer, + const struct sockaddr_storage *ss, + const void *local_ip) +{ + struct ovpn_bind *bind; + size_t ip_len; + + lockdep_assert_held(&peer->lock); + + /* create new ovpn_bind object */ + bind =3D ovpn_bind_from_sockaddr(ss); + if (IS_ERR(bind)) + return PTR_ERR(bind); + + if (ss->ss_family =3D=3D AF_INET) { + ip_len =3D sizeof(struct in_addr); + } else if (ss->ss_family =3D=3D AF_INET6) { + ip_len =3D sizeof(struct in6_addr); + } else { + net_dbg_ratelimited("%s: invalid family %u for remote endpoint for peer = %u\n", + netdev_name(peer->ovpn->dev), + ss->ss_family, peer->id); + kfree(bind); + return -EINVAL; + } + + memcpy(&bind->local, local_ip, ip_len); + + /* set binding */ + ovpn_bind_reset(peer, bind); + + return 0; +} + +/* variable name __tbl2 needs to be different from __tbl1 + * in the macro below to avoid confusing clang + */ +#define ovpn_get_hash_slot(_tbl, _key, _key_len) ({ \ + typeof(_tbl) *__tbl2 =3D &(_tbl); \ + jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl2); \ +}) + +#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \ + typeof(_tbl) *__tbl1 =3D &(_tbl); \ + &(*__tbl1)[ovpn_get_hash_slot(*__tbl1, _key, _key_len)];\ +}) + +/** + * ovpn_peer_endpoints_update - update remote or local endpoint for peer + * @peer: peer to update the remote endpoint for + * @skb: incoming packet to retrieve the source/destination address from + */ +void ovpn_peer_endpoints_update(struct ovpn_peer *peer, struct sk_buff *sk= b) +{ + struct hlist_nulls_head *nhead; + struct sockaddr_storage ss; + struct sockaddr_in6 *sa6; + bool reset_cache =3D false; + struct sockaddr_in *sa; + struct ovpn_bind *bind; + const void *local_ip; + size_t salen =3D 0; + + spin_lock_bh(&peer->lock); + bind =3D rcu_dereference_protected(peer->bind, + lockdep_is_held(&peer->lock)); + if (unlikely(!bind)) + goto unlock; + + switch (skb->protocol) { + case htons(ETH_P_IP): + /* float check */ + if (unlikely(!ovpn_bind_skb_src_match(bind, skb))) { + /* unconditionally save local endpoint in case + * of float, as it may have changed as well + */ + local_ip =3D &ip_hdr(skb)->daddr; + sa =3D (struct sockaddr_in *)&ss; + sa->sin_family =3D AF_INET; + sa->sin_addr.s_addr =3D ip_hdr(skb)->saddr; + sa->sin_port =3D udp_hdr(skb)->source; + salen =3D sizeof(*sa); + reset_cache =3D true; + break; + } + + /* if no float happened, let's double check if the local endpoint + * has changed + */ + if (unlikely(bind->local.ipv4.s_addr !=3D ip_hdr(skb)->daddr)) { + net_dbg_ratelimited("%s: learning local IPv4 for peer %d (%pI4 -> %pI4)= \n", + netdev_name(peer->ovpn->dev), + peer->id, &bind->local.ipv4.s_addr, + &ip_hdr(skb)->daddr); + bind->local.ipv4.s_addr =3D ip_hdr(skb)->daddr; + reset_cache =3D true; + } + break; + case htons(ETH_P_IPV6): + /* float check */ + if (unlikely(!ovpn_bind_skb_src_match(bind, skb))) { + /* unconditionally save local endpoint in case + * of float, as it may have changed as well + */ + local_ip =3D &ipv6_hdr(skb)->daddr; + sa6 =3D (struct sockaddr_in6 *)&ss; + sa6->sin6_family =3D AF_INET6; + sa6->sin6_addr =3D ipv6_hdr(skb)->saddr; + sa6->sin6_port =3D udp_hdr(skb)->source; + sa6->sin6_scope_id =3D ipv6_iface_scope_id(&ipv6_hdr(skb)->saddr, + skb->skb_iif); + salen =3D sizeof(*sa6); + reset_cache =3D true; + break; + } + + /* if no float happened, let's double check if the local endpoint + * has changed + */ + if (unlikely(!ipv6_addr_equal(&bind->local.ipv6, + &ipv6_hdr(skb)->daddr))) { + net_dbg_ratelimited("%s: learning local IPv6 for peer %d (%pI6c -> %pI6= c\n", + netdev_name(peer->ovpn->dev), + peer->id, &bind->local.ipv6, + &ipv6_hdr(skb)->daddr); + bind->local.ipv6 =3D ipv6_hdr(skb)->daddr; + reset_cache =3D true; + } + break; + default: + goto unlock; + } + + if (unlikely(reset_cache)) + dst_cache_reset(&peer->dst_cache); + + /* if the peer did not float, we can bail out now */ + if (likely(!salen)) + goto unlock; + + if (unlikely(ovpn_peer_reset_sockaddr(peer, + (struct sockaddr_storage *)&ss, + local_ip) < 0)) + goto unlock; + + net_dbg_ratelimited("%s: peer %d floated to %pIScp", + netdev_name(peer->ovpn->dev), peer->id, &ss); + + spin_unlock_bh(&peer->lock); + + /* rehashing is required only in MP mode as P2P has one peer + * only and thus there is no hashtable + */ + if (peer->ovpn->mode =3D=3D OVPN_MODE_MP) { + spin_lock_bh(&peer->ovpn->lock); + spin_lock_bh(&peer->lock); + bind =3D rcu_dereference_protected(peer->bind, + lockdep_is_held(&peer->lock)); + if (unlikely(!bind)) { + spin_unlock_bh(&peer->lock); + spin_unlock_bh(&peer->ovpn->lock); + return; + } + + /* This function may be invoked concurrently, therefore another + * float may have happened in parallel: perform rehashing + * using the peer->bind->remote directly as key + */ + + switch (bind->remote.in4.sin_family) { + case AF_INET: + salen =3D sizeof(*sa); + break; + case AF_INET6: + salen =3D sizeof(*sa6); + break; + } + + /* remove old hashing */ + hlist_nulls_del_init_rcu(&peer->hash_entry_transp_addr); + /* re-add with new transport address */ + nhead =3D ovpn_get_hash_head(peer->ovpn->peers->by_transp_addr, + &bind->remote, salen); + hlist_nulls_add_head_rcu(&peer->hash_entry_transp_addr, nhead); + spin_unlock_bh(&peer->lock); + spin_unlock_bh(&peer->ovpn->lock); + } + return; +unlock: + spin_unlock_bh(&peer->lock); +} + /** * ovpn_peer_release_rcu - RCU callback performing last peer release steps * @head: RCU member of the ovpn_peer @@ -230,19 +430,6 @@ static struct in6_addr ovpn_nexthop_from_skb6(struct s= k_buff *skb) return rt->rt6i_gateway; } =20 -/* variable name __tbl2 needs to be different from __tbl1 - * in the macro below to avoid confusing clang - */ -#define ovpn_get_hash_slot(_tbl, _key, _key_len) ({ \ - typeof(_tbl) *__tbl2 =3D &(_tbl); \ - jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl2); \ -}) - -#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \ - typeof(_tbl) *__tbl1 =3D &(_tbl); \ - &(*__tbl1)[ovpn_get_hash_slot(*__tbl1, _key, _key_len)];\ -}) - /** * ovpn_peer_get_by_vpn_addr4 - retrieve peer by its VPN IPv4 address * @ovpn: the openvpn instance to search diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h index e747c4b210642db990222986a80bb37c9a0413fe..f1288734ff100ee76b0c41ebb6d= c71725ea33261 100644 --- a/drivers/net/ovpn/peer.h +++ b/drivers/net/ovpn/peer.h @@ -153,4 +153,6 @@ bool ovpn_peer_check_by_src(struct ovpn_priv *ovpn, str= uct sk_buff *skb, void ovpn_peer_keepalive_set(struct ovpn_peer *peer, u32 interval, u32 tim= eout); void ovpn_peer_keepalive_work(struct work_struct *work); =20 +void ovpn_peer_endpoints_update(struct ovpn_peer *peer, struct sk_buff *sk= b); + #endif /* _NET_OVPN_OVPNPEER_H_ */ --=20 2.48.1