net/tcp: Add TCP-AO SNE support (64382c71) · Commits · git / linux-net

include/net/tcp_ao.h

+21 −1

Original line number	Diff line number	Diff line
		@@ -95,6 +95,25 @@ struct tcp_ao_info {
		__unused :31;
		__be32 lisn;
		__be32 risn;
		/* Sequence Number Extension (SNE) are upper 4 bytes for SEQ,
		* that protect TCP-AO connection from replayed old TCP segments.
		* See RFC5925 (6.2).
		* In order to get correct SNE, there's a helper tcp_ao_compute_sne().
		* It needs SEQ basis to understand whereabouts are lower SEQ numbers.
		* According to that basis vector, it can provide incremented SNE
		* when SEQ rolls over or provide decremented SNE when there's
		* a retransmitted segment from before-rolling over.
		* - for request sockets such basis is rcv_isn/snt_isn, which seems
		* good enough as it's unexpected to receive 4 Gbytes on reqsk.
		* - for full sockets the basis is rcv_nxt/snd_una. snd_una is
		* taken instead of snd_nxt as currently it's easier to track
		* in tcp_snd_una_update(), rather than updating SNE in all
		* WRITE_ONCE(tp->snd_nxt, ...)
		* - for time-wait sockets the basis is tw_rcv_nxt/tw_snd_nxt.
		* tw_snd_nxt is not expected to change, while tw_rcv_nxt may.
		*/
		u32 snd_sne;
		u32 rcv_sne;
		refcount_t refcnt; /* Protects twsk destruction */
		struct rcu_head rcu;
		};
		@@ -147,6 +166,7 @@ enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk,
		const struct sk_buff *skb, unsigned short int family,
		const struct request_sock *req,
		const struct tcp_ao_hdr *aoh);
		u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq);
		struct tcp_ao_key tcp_ao_do_lookup(const struct sock sk,
		const union tcp_ao_addr *addr,
		int family, int sndid, int rcvid);
		@@ -156,7 +176,7 @@ int tcp_ao_hash_hdr(unsigned short family, char *ao_hash,
		const union tcp_ao_addr *saddr,
		const struct tcphdr *th, u32 sne);
		int tcp_ao_prepare_reset(const struct sock sk, struct sk_buff skb,
		const struct tcp_ao_hdr *aoh, int l3index,
		const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
		struct tcp_ao_key key, char traffic_key,
		bool allocated_traffic_key, u8 keyid, u32 *sne);

net/ipv4/tcp_ao.c

+37 −9

Original line number	Diff line number	Diff line
		@@ -401,6 +401,21 @@ static int tcp_ao_hash_pseudoheader(unsigned short int family,
		return -EAFNOSUPPORT;
		}

		u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq)
		{
		u32 sne = next_sne;

		if (before(seq, next_seq)) {
		if (seq > next_seq)
		sne--;
		} else {
		if (seq < next_seq)
		sne++;
		}

		return sne;
		}

		/* tcp_ao_hash_sne(struct tcp_sigpool *hp)
		* @hp - used for hashing
		* @sne - sne value
		@@ -611,7 +626,7 @@ struct tcp_ao_key tcp_v4_ao_lookup(const struct sock sk, struct sock *addr_sk,
		}

		int tcp_ao_prepare_reset(const struct sock sk, struct sk_buff skb,
		const struct tcp_ao_hdr *aoh, int l3index,
		const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
		struct tcp_ao_key key, char traffic_key,
		bool allocated_traffic_key, u8 keyid, u32 *sne)
		{
		@@ -639,7 +654,7 @@ int tcp_ao_prepare_reset(const struct sock sk, struct sk_buff skb,

		sisn = htonl(tcp_rsk(req)->rcv_isn);
		disn = htonl(tcp_rsk(req)->snt_isn);
		*sne = 0;
		*sne = tcp_ao_compute_sne(0, tcp_rsk(req)->snt_isn, seq);
		} else {
		sisn = th->seq;
		disn = 0;
		@@ -670,11 +685,15 @@ int tcp_ao_prepare_reset(const struct sock sk, struct sk_buff skb,
		keyid = (key)->rcvid;
		} else {
		struct tcp_ao_key *rnext_key;
		u32 snd_basis;

		if (sk->sk_state == TCP_TIME_WAIT)
		if (sk->sk_state == TCP_TIME_WAIT) {
		ao_info = rcu_dereference(tcp_twsk(sk)->ao_info);
		else
		snd_basis = tcp_twsk(sk)->tw_snd_nxt;
		} else {
		ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
		snd_basis = tcp_sk(sk)->snd_una;
		}
		if (!ao_info)
		return -ENOENT;

		@@ -684,7 +703,8 @@ int tcp_ao_prepare_reset(const struct sock sk, struct sk_buff skb,
		traffic_key = snd_other_key(key);
		rnext_key = READ_ONCE(ao_info->rnext_key);
		*keyid = rnext_key->rcvid;
		*sne = 0;
		*sne = tcp_ao_compute_sne(READ_ONCE(ao_info->snd_sne),
		snd_basis, seq);
		}
		return 0;
		}
		@@ -698,6 +718,7 @@ int tcp_ao_transmit_skb(struct sock sk, struct sk_buff skb,
		struct tcp_ao_info *ao;
		void *tkey_buf = NULL;
		u8 *traffic_key;
		u32 sne;

		ao = rcu_dereference_protected(tcp_sk(sk)->ao_info,
		lockdep_sock_is_held(sk));
		@@ -717,8 +738,10 @@ int tcp_ao_transmit_skb(struct sock sk, struct sk_buff skb,
		tp->af_specific->ao_calc_key_sk(key, traffic_key,
		sk, ao->lisn, disn, true);
		}
		sne = tcp_ao_compute_sne(READ_ONCE(ao->snd_sne), READ_ONCE(tp->snd_una),
		ntohl(th->seq));
		tp->af_specific->calc_ao_hash(hash_location, key, sk, skb, traffic_key,
		hash_location - (u8 *)th, 0);
		hash_location - (u8 *)th, sne);
		kfree(tkey_buf);
		return 0;
		}
		@@ -846,7 +869,8 @@ tcp_inbound_ao_hash(struct sock sk, const struct sk_buff skb,
		if (unlikely(th->syn && !th->ack))
		goto verify_hash;

		sne = 0;
		sne = tcp_ao_compute_sne(info->rcv_sne, tcp_sk(sk)->rcv_nxt,
		ntohl(th->seq));
		/* Established socket, traffic key are cached */
		traffic_key = rcv_other_key(key);
		err = tcp_ao_verify_hash(sk, skb, family, info, aoh, key,
		@@ -881,14 +905,16 @@ tcp_inbound_ao_hash(struct sock sk, const struct sk_buff skb,
		if ((1 << sk->sk_state) & (TCPF_LISTEN \| TCPF_NEW_SYN_RECV)) {
		/* Make the initial syn the likely case here */
		if (unlikely(req)) {
		sne = 0;
		sne = tcp_ao_compute_sne(0, tcp_rsk(req)->rcv_isn,
		ntohl(th->seq));
		sisn = htonl(tcp_rsk(req)->rcv_isn);
		disn = htonl(tcp_rsk(req)->snt_isn);
		} else if (unlikely(th->ack && !th->syn)) {
		/* Possible syncookie packet */
		sisn = htonl(ntohl(th->seq) - 1);
		disn = htonl(ntohl(th->ack_seq) - 1);
		sne = 0;
		sne = tcp_ao_compute_sne(0, ntohl(sisn),
		ntohl(th->seq));
		} else if (unlikely(!th->syn)) {
		/* no way to figure out initial sisn/disn - drop */
		return SKB_DROP_REASON_TCP_FLAGS;
		@@ -986,6 +1012,7 @@ void tcp_ao_connect_init(struct sock *sk)
		tp->tcp_header_len += tcp_ao_len(key);

		ao_info->lisn = htonl(tp->write_seq);
		ao_info->snd_sne = 0;
		} else {
		/* Can't happen: tcp_connect() verifies that there's
		* at least one tcp-ao key that matches the remote peer.
		@@ -1021,6 +1048,7 @@ void tcp_ao_finish_connect(struct sock sk, struct sk_buff skb)
		return;

		WRITE_ONCE(ao->risn, tcp_hdr(skb)->seq);
		ao->rcv_sne = 0;

		hlist_for_each_entry_rcu(key, &ao->head, node)
		tcp_ao_cache_traffic_keys(sk, ao, key);

net/ipv4/tcp_input.c

+28 −0

Original line number	Diff line number	Diff line
		@@ -3576,9 +3576,18 @@ static inline bool tcp_may_update_window(const struct tcp_sock *tp,
		static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack)
		{
		u32 delta = ack - tp->snd_una;
		#ifdef CONFIG_TCP_AO
		struct tcp_ao_info *ao;
		#endif

		sock_owned_by_me((struct sock *)tp);
		tp->bytes_acked += delta;
		#ifdef CONFIG_TCP_AO
		ao = rcu_dereference_protected(tp->ao_info,
		lockdep_sock_is_held((struct sock *)tp));
		if (ao && ack < tp->snd_una)
		ao->snd_sne++;
		#endif
		tp->snd_una = ack;
		}

		@@ -3586,9 +3595,18 @@ static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack)
		static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq)
		{
		u32 delta = seq - tp->rcv_nxt;
		#ifdef CONFIG_TCP_AO
		struct tcp_ao_info *ao;
		#endif

		sock_owned_by_me((struct sock *)tp);
		tp->bytes_received += delta;
		#ifdef CONFIG_TCP_AO
		ao = rcu_dereference_protected(tp->ao_info,
		lockdep_sock_is_held((struct sock *)tp));
		if (ao && seq < tp->rcv_nxt)
		ao->rcv_sne++;
		#endif
		WRITE_ONCE(tp->rcv_nxt, seq);
		}

		@@ -6456,6 +6474,16 @@ static int tcp_rcv_synsent_state_process(struct sock sk, struct sk_buff skb,
		* simultaneous connect with crossed SYNs.
		* Particularly, it can be connect to self.
		*/
		#ifdef CONFIG_TCP_AO
		struct tcp_ao_info *ao;

		ao = rcu_dereference_protected(tp->ao_info,
		lockdep_sock_is_held(sk));
		if (ao) {
		WRITE_ONCE(ao->risn, th->seq);
		ao->rcv_sne = 0;
		}
		#endif
		tcp_set_state(sk, TCP_SYN_RECV);

		if (tp->rx_opt.saw_tstamp) {

net/ipv4/tcp_ipv4.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -676,7 +676,7 @@ static bool tcp_v4_ao_sign_reset(const struct sock sk, struct sk_buff skb,
		u8 keyid;

		rcu_read_lock();
		if (tcp_ao_prepare_reset(sk, skb, aoh, l3index,
		if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
		&key, &traffic_key, &allocated_traffic_key,
		&keyid, &ao_sne))
		goto out;
		@@ -1034,6 +1034,7 @@ static void tcp_v4_timewait_ack(struct sock sk, struct sk_buff skb)
		struct tcp_ao_key *rnext_key;

		key.traffic_key = snd_other_key(key.ao_key);
		key.sne = READ_ONCE(ao_info->snd_sne);
		rnext_key = READ_ONCE(ao_info->rnext_key);
		key.rcv_next = rnext_key->rcvid;
		key.type = TCP_KEY_AO;

net/ipv4/tcp_minisocks.c

+14 −1

Original line number	Diff line number	Diff line
		@@ -51,6 +51,18 @@ tcp_timewait_check_oow_rate_limit(struct inet_timewait_sock *tw,
		return TCP_TW_SUCCESS;
		}

		static void twsk_rcv_nxt_update(struct tcp_timewait_sock *tcptw, u32 seq)
		{
		#ifdef CONFIG_TCP_AO
		struct tcp_ao_info *ao;

		ao = rcu_dereference(tcptw->ao_info);
		if (unlikely(ao && seq < tcptw->tw_rcv_nxt))
		WRITE_ONCE(ao->rcv_sne, ao->rcv_sne + 1);
		#endif
		tcptw->tw_rcv_nxt = seq;
		}

		/*
		* * Main purpose of TIME-WAIT state is to close connection gracefully,
		* when one of ends sits in LAST-ACK or CLOSING retransmitting FIN
		@@ -136,7 +148,8 @@ tcp_timewait_state_process(struct inet_timewait_sock tw, struct sk_buff skb,

		/* FIN arrived, enter true time-wait state. */
		tw->tw_substate = TCP_TIME_WAIT;
		tcptw->tw_rcv_nxt = TCP_SKB_CB(skb)->end_seq;
		twsk_rcv_nxt_update(tcptw, TCP_SKB_CB(skb)->end_seq);

		if (tmp_opt.saw_tstamp) {
		tcptw->tw_ts_recent_stamp = ktime_get_seconds();
		tcptw->tw_ts_recent = tmp_opt.rcv_tsval;