diff options
| -rw-r--r-- | net/ipv4/syncookies.c | 6 | ||||
| -rw-r--r-- | net/mptcp/Makefile | 1 | ||||
| -rw-r--r-- | net/mptcp/ctrl.c | 1 | ||||
| -rw-r--r-- | net/mptcp/protocol.h | 20 | ||||
| -rw-r--r-- | net/mptcp/subflow.c | 14 | ||||
| -rw-r--r-- | net/mptcp/syncookies.c | 132 |
6 files changed, 174 insertions, 0 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 54838ee2e8d4..11b20474be83 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -212,6 +212,12 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, refcount_set(&req->rsk_refcnt, 1); tcp_sk(child)->tsoffset = tsoff; sock_rps_save_rxhash(child, skb); + + if (tcp_rsk(req)->drop_req) { + refcount_set(&req->rsk_refcnt, 2); + return child; + } + if (inet_csk_reqsk_queue_add(sk, req, child)) return child; diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile index 2360cbd27d59..a611968be4d7 100644 --- a/net/mptcp/Makefile +++ b/net/mptcp/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_MPTCP) += mptcp.o mptcp-y := protocol.o subflow.o options.o token.o crypto.o ctrl.o pm.o diag.o \ mib.o pm_netlink.o +obj-$(CONFIG_SYN_COOKIES) += syncookies.o obj-$(CONFIG_INET_MPTCP_DIAG) += mptcp_diag.o mptcp_crypto_test-objs := crypto_test.o diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c index 8e39585d37f3..54b888f94009 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -112,6 +112,7 @@ static struct pernet_operations mptcp_pernet_ops = { void __init mptcp_init(void) { + mptcp_join_cookie_init(); mptcp_proto_init(); if (register_pernet_subsys(&mptcp_pernet_ops) < 0) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index d76d3b40d69e..60b27d44c184 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -506,4 +506,24 @@ static inline bool subflow_simultaneous_connect(struct sock *sk) !subflow->conn_finished; } +#ifdef CONFIG_SYN_COOKIES +void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req, + struct sk_buff *skb); +bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req, + struct sk_buff *skb); +void __init mptcp_join_cookie_init(void); +#else +static inline void +subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req, + struct sk_buff *skb) {} +static inline bool +mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req, + struct sk_buff *skb) +{ + return false; +} + +static inline void mptcp_join_cookie_init(void) {} +#endif + #endif /* __MPTCP_PROTOCOL_H */ diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 3d346572d4c9..a4cc4591bd4e 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -173,6 +173,12 @@ again: subflow_req->token = mp_opt.token; subflow_req->remote_nonce = mp_opt.nonce; subflow_req->msk = subflow_token_join_request(req, skb); + + if (unlikely(req->syncookie) && subflow_req->msk) { + if (mptcp_can_accept_new_subflow(subflow_req->msk)) + subflow_init_req_cookie_join_save(subflow_req, skb); + } + pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, subflow_req->remote_nonce, subflow_req->msk); } @@ -207,6 +213,14 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req, subflow_req->mp_capable = 1; subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; + } else if (mp_opt.mp_join && listener->request_mptcp) { + if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) + return -EINVAL; + + if (mptcp_can_accept_new_subflow(subflow_req->msk)) + subflow_req->mp_join = 1; + + subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; } return 0; diff --git a/net/mptcp/syncookies.c b/net/mptcp/syncookies.c new file mode 100644 index 000000000000..6eb992789b50 --- /dev/null +++ b/net/mptcp/syncookies.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/skbuff.h> + +#include "protocol.h" + +/* Syncookies do not work for JOIN requests. + * + * Unlike MP_CAPABLE, where the ACK cookie contains the needed MPTCP + * options to reconstruct the initial syn state, MP_JOIN does not contain + * the token to obtain the mptcp socket nor the server-generated nonce + * that was used in the cookie SYN/ACK response. + * + * Keep a small best effort state table to store the syn/synack data, + * indexed by skb hash. + * + * A MP_JOIN SYN packet handled by syn cookies is only stored if the 32bit + * token matches a known mptcp connection that can still accept more subflows. + * + * There is no timeout handling -- state is only re-constructed + * when the TCP ACK passed the cookie validation check. + */ + +struct join_entry { + u32 token; + u32 remote_nonce; + u32 local_nonce; + u8 join_id; + u8 local_id; + u8 backup; + u8 valid; +}; + +#define COOKIE_JOIN_SLOTS 1024 + +static struct join_entry join_entries[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp; +static spinlock_t join_entry_locks[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp; + +static u32 mptcp_join_entry_hash(struct sk_buff *skb, struct net *net) +{ + u32 i = skb_get_hash(skb) ^ net_hash_mix(net); + + return i % ARRAY_SIZE(join_entries); +} + +static void mptcp_join_store_state(struct join_entry *entry, + const struct mptcp_subflow_request_sock *subflow_req) +{ + entry->token = subflow_req->token; + entry->remote_nonce = subflow_req->remote_nonce; + entry->local_nonce = subflow_req->local_nonce; + entry->backup = subflow_req->backup; + entry->join_id = subflow_req->remote_id; + entry->local_id = subflow_req->local_id; + entry->valid = 1; +} + +void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req, + struct sk_buff *skb) +{ + struct net *net = read_pnet(&subflow_req->sk.req.ireq_net); + u32 i = mptcp_join_entry_hash(skb, net); + + /* No use in waiting if other cpu is already using this slot -- + * would overwrite the data that got stored. + */ + spin_lock_bh(&join_entry_locks[i]); + mptcp_join_store_state(&join_entries[i], subflow_req); + spin_unlock_bh(&join_entry_locks[i]); +} + +/* Called for a cookie-ack with MP_JOIN option present. + * Look up the saved state based on skb hash & check token matches msk + * in same netns. + * + * Caller will check msk can still accept another subflow. The hmac + * present in the cookie ACK mptcp option space will be checked later. + */ +bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req, + struct sk_buff *skb) +{ + struct net *net = read_pnet(&subflow_req->sk.req.ireq_net); + u32 i = mptcp_join_entry_hash(skb, net); + struct mptcp_sock *msk; + struct join_entry *e; + + e = &join_entries[i]; + + spin_lock_bh(&join_entry_locks[i]); + + if (e->valid == 0) { + spin_unlock_bh(&join_entry_locks[i]); + return false; + } + + e->valid = 0; + + msk = mptcp_token_get_sock(e->token); + if (!msk) { + spin_unlock_bh(&join_entry_locks[i]); + return false; + } + + /* If this fails, the token got re-used in the mean time by another + * mptcp socket in a different netns, i.e. entry is outdated. + */ + if (!net_eq(sock_net((struct sock *)msk), net)) + goto err_put; + + subflow_req->remote_nonce = e->remote_nonce; + subflow_req->local_nonce = e->local_nonce; + subflow_req->backup = e->backup; + subflow_req->remote_id = e->join_id; + subflow_req->token = e->token; + subflow_req->msk = msk; + spin_unlock_bh(&join_entry_locks[i]); + return true; + +err_put: + spin_unlock_bh(&join_entry_locks[i]); + sock_put((struct sock *)msk); + return false; +} + +void __init mptcp_join_cookie_init(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(join_entry_locks); i++) + spin_lock_init(&join_entry_locks[i]); + + BUILD_BUG_ON(ARRAY_SIZE(join_entry_locks) != ARRAY_SIZE(join_entries)); +} |