Re: [PATCH v4 bpf-next 06/11] tcp: Migrate TCP_NEW_SYN_RECV requests at retransmitting SYN+ACKs.
From: Martin KaFai Lau <hidden>
Date: 2021-05-05 04:56:46
Also in:
bpf, lkml
On Tue, Apr 27, 2021 at 12:46:18PM +0900, Kuniyuki Iwashima wrote: [ ... ]
quoted hunk ↗ jump to hunk
diff --git a/net/core/request_sock.c b/net/core/request_sock.c index 82cf9fbe2668..08c37ecd923b 100644 --- a/net/core/request_sock.c +++ b/net/core/request_sock.c@@ -151,6 +151,7 @@ struct request_sock *reqsk_clone(struct request_sock *req, struct sock *sk) memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end, req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end)); + sk_node_init(&nreq_sk->sk_node);
This belongs to patch 5. "rsk_refcnt" also needs to be 0 instead of staying uninitialized after reqsk_clone() returned.
quoted hunk ↗ jump to hunk
nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping; #ifdef CONFIG_XPS nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 851992405826..dc984d1f352e 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c@@ -695,10 +695,20 @@ int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req) } EXPORT_SYMBOL(inet_rtx_syn_ack); +static void reqsk_queue_migrated(struct request_sock_queue *queue, + const struct request_sock *req) +{ + if (req->num_timeout == 0) + atomic_inc(&queue->young); + atomic_inc(&queue->qlen); +} + static void reqsk_migrate_reset(struct request_sock *req) { + req->saved_syn = NULL; + inet_rsk(req)->ireq_opt = NULL; #if IS_ENABLED(CONFIG_IPV6) - inet_rsk(req)->ipv6_opt = NULL; + inet_rsk(req)->pktopts = NULL; #endif }@@ -741,16 +751,37 @@ EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put); static void reqsk_timer_handler(struct timer_list *t) { - struct request_sock *req = from_timer(req, t, rsk_timer); - struct sock *sk_listener = req->rsk_listener; - struct net *net = sock_net(sk_listener); - struct inet_connection_sock *icsk = inet_csk(sk_listener); - struct request_sock_queue *queue = &icsk->icsk_accept_queue; + struct request_sock *req = from_timer(req, t, rsk_timer), *nreq = NULL, *oreq = req;
nit. This line is too long. Lets move the new "*nreq" and "*oreg" to a new line and keep the current "*req" line as is: struct request_sock *req = from_timer(req, t, rsk_timer); struct request_sock *oreq = req, *nreq = NULL;
+ struct sock *sk_listener = req->rsk_listener, *nsk = NULL;
"*nsk" can be moved into the following "!= TCP_LISTEN" case below. Keep the current "*sk_listener" line as is.
+ struct inet_connection_sock *icsk;
+ struct request_sock_queue *queue;
+ struct net *net;
int max_syn_ack_retries, qlen, expire = 0, resend = 0;
- if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
- goto drop;
+ if (inet_sk_state_load(sk_listener) != TCP_LISTEN) {struct sock *nsk;
+ nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL); + if (!nsk) + goto drop; + + nreq = reqsk_clone(req, nsk); + if (!nreq) + goto drop; + + /* The new timer for the cloned req can decrease the 2 + * by calling inet_csk_reqsk_queue_drop_and_put(), so + * hold another count to prevent use-after-free and + * call reqsk_put() just before return. + */ + refcount_set(&nreq->rsk_refcnt, 2 + 1); + timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED); + reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req); + + req = nreq; + sk_listener = nsk; + }