tcp: Factorise cookie-independent fields initialisation in cookie_v[46]_check().

We will support arbitrary SYN Cookie with BPF, and then some reqsk fields
are initialised in kfunc, and others are done in cookie_v[46]_check().

This patch factorises the common part as cookie_tcp_reqsk_init() and
calls it in cookie_tcp_reqsk_alloc() to minimise the discrepancy between
cookie_v[46]_check().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231129022924.96156-8-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 1e3783c97e28be61bbea1a2570f5ec6a0c700478..f4bcd4822fe078e2393883099f07fdd4b5b1f851 100644 (file)
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -285,10 +285,43 @@ bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt,
 }
 EXPORT_SYMBOL(cookie_ecn_ok);
 
+static int cookie_tcp_reqsk_init(struct sock *sk, struct sk_buff *skb,
+                                struct request_sock *req)
+{
+       struct inet_request_sock *ireq = inet_rsk(req);
+       struct tcp_request_sock *treq = tcp_rsk(req);
+       const struct tcphdr *th = tcp_hdr(skb);
+
+       req->num_retrans = 0;
+
+       ireq->ir_num = ntohs(th->dest);
+       ireq->ir_rmt_port = th->source;
+       ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
+       ireq->ir_mark = inet_request_mark(sk, skb);
+
+       if (IS_ENABLED(CONFIG_SMC))
+               ireq->smc_ok = 0;
+
+       treq->snt_synack = 0;
+       treq->tfo_listener = false;
+       treq->txhash = net_tx_rndhash();
+       treq->rcv_isn = ntohl(th->seq) - 1;
+       treq->snt_isn = ntohl(th->ack_seq) - 1;
+       treq->syn_tos = TCP_SKB_CB(skb)->ip_dsfield;
+       treq->req_usec_ts = false;
+
+#if IS_ENABLED(CONFIG_MPTCP)
+       treq->is_mptcp = sk_is_mptcp(sk);
+       if (treq->is_mptcp)
+               return mptcp_subflow_init_cookie_req(req, sk, skb);
+#endif
+
+       return 0;
+}
+
 struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
                                            struct sock *sk, struct sk_buff *skb)
 {
-       struct tcp_request_sock *treq;
        struct request_sock *req;
 
        if (sk_is_mptcp(sk))
@@ -299,22 +332,10 @@ struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
        if (!req)
                return NULL;
 
-       treq = tcp_rsk(req);
-
-       treq->syn_tos = TCP_SKB_CB(skb)->ip_dsfield;
-       treq->req_usec_ts = false;
-
-#if IS_ENABLED(CONFIG_MPTCP)
-       treq->is_mptcp = sk_is_mptcp(sk);
-       if (treq->is_mptcp) {
-               int err = mptcp_subflow_init_cookie_req(req, sk, skb);
-
-               if (err) {
-                       reqsk_free(req);
-                       return NULL;
-               }
+       if (cookie_tcp_reqsk_init(sk, skb, req)) {
+               reqsk_free(req);
+               return NULL;
        }
-#endif
 
        return req;
 }
@@ -376,28 +397,15 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 
        ireq = inet_rsk(req);
        treq = tcp_rsk(req);
-       treq->rcv_isn           = ntohl(th->seq) - 1;
-       treq->snt_isn           = ntohl(th->ack_seq) - 1;
        treq->ts_off            = tsoff;
-       treq->txhash            = net_tx_rndhash();
        req->mss                = mss;
-       ireq->ir_num            = ntohs(th->dest);
-       ireq->ir_rmt_port       = th->source;
        sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
        sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
-       ireq->ir_mark           = inet_request_mark(sk, skb);
        ireq->snd_wscale        = tcp_opt.snd_wscale;
        ireq->sack_ok           = tcp_opt.sack_ok;
        ireq->wscale_ok         = tcp_opt.wscale_ok;
        ireq->tstamp_ok         = tcp_opt.saw_tstamp;
        req->ts_recent          = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
-       treq->snt_synack        = 0;
-       treq->tfo_listener      = false;
-
-       if (IS_ENABLED(CONFIG_SMC))
-               ireq->smc_ok = 0;
-
-       ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
 
        /* We throwed the options of the initial SYN away, so we hope
         * the ACK carries the same options again (see RFC1122 4.2.3.8)
@@ -409,8 +417,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 
        tcp_ao_syncookie(sk, skb, req, AF_INET);
 
-       req->num_retrans = 0;
-
        /*
         * We need to lookup the route here to get at the correct
         * window size. We should better make sure that the window size

diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 12b1809245f99920bdcea5bfcbd4f6d1af803c8a..e0a9220d1536a155a7be277a01453344d431dee8 100644 (file)
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -178,11 +178,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 
        ireq = inet_rsk(req);
        treq = tcp_rsk(req);
-       treq->tfo_listener = false;
 
        req->mss = mss;
-       ireq->ir_rmt_port = th->source;
-       ireq->ir_num = ntohs(th->dest);
        ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
        ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 
@@ -196,31 +193,20 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
                ireq->pktopts = skb;
        }
 
-       ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
        /* So that link locals have meaning */
        if (!sk->sk_bound_dev_if &&
            ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
                ireq->ir_iif = tcp_v6_iif(skb);
 
-       ireq->ir_mark = inet_request_mark(sk, skb);
-
-       req->num_retrans = 0;
        ireq->snd_wscale        = tcp_opt.snd_wscale;
        ireq->sack_ok           = tcp_opt.sack_ok;
        ireq->wscale_ok         = tcp_opt.wscale_ok;
        ireq->tstamp_ok         = tcp_opt.saw_tstamp;
        req->ts_recent          = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
-       treq->snt_synack        = 0;
-       treq->rcv_isn = ntohl(th->seq) - 1;
-       treq->snt_isn = ntohl(th->ack_seq) - 1;
        treq->ts_off = tsoff;
-       treq->txhash = net_tx_rndhash();
 
        tcp_ao_syncookie(sk, skb, req, AF_INET6);
 
-       if (IS_ENABLED(CONFIG_SMC))
-               ireq->smc_ok = 0;
-
        /*
         * We need to lookup the dst_entry to get the correct window size.
         * This is taken from tcp_v6_syn_recv_sock.  Somebody please enlighten