From d389424e00f9097cd24b3df4ca0ab7221f140eeb Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 22 Sep 2005 07:57:21 -0300 Subject: [LLC]: Fix the accept path Borrowing the structure of TCP/IP for this. On the receive of new connections I was bh_lock_socking the _new_ sock, not the listening one, duh, now it survives the ssh connections storm I've been using to test this specific bug. Also fixes send side skb sock accounting. Signed-off-by: Arnaldo Carvalho de Melo --- net/llc/llc_conn.c | 142 +++++++++++++++++++++++++++++++++++------------------ 1 file changed, 95 insertions(+), 47 deletions(-) (limited to 'net/llc/llc_conn.c') diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c index 76f94e0d840d..e10ce5adb104 100644 --- a/net/llc/llc_conn.c +++ b/net/llc/llc_conn.c @@ -58,7 +58,7 @@ int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ; int llc_conn_state_process(struct sock *sk, struct sk_buff *skb) { int rc; - struct llc_sock *llc = llc_sk(sk); + struct llc_sock *llc = llc_sk(skb->sk); struct llc_conn_state_ev *ev = llc_conn_ev(skb); /* @@ -68,7 +68,10 @@ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb) */ skb_get(skb); ev->ind_prim = ev->cfm_prim = 0; - rc = llc_conn_service(sk, skb); /* sending event to state machine */ + /* + * Send event to state machine + */ + rc = llc_conn_service(skb->sk, skb); if (unlikely(rc != 0)) { printk(KERN_ERR "%s: llc_conn_service failed\n", __FUNCTION__); goto out_kfree_skb; @@ -100,18 +103,14 @@ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb) kfree_skb(skb); } break; - case LLC_CONN_PRIM: { - struct sock *parent = skb->sk; - - skb_orphan(skb); + case LLC_CONN_PRIM: /* - * Set the skb->sk to the new struct sock, so that at accept - * type the upper layer can get the newly created struct sock. + * Can't be sock_queue_rcv_skb, because we have to leave the + * skb->sk pointing to the newly created struct sock in + * llc_conn_handler. -acme */ - skb->sk = sk; - skb_queue_tail(&parent->sk_receive_queue, skb); - sk->sk_state_change(parent); - } + skb_queue_tail(&sk->sk_receive_queue, skb); + sk->sk_state_change(sk); break; case LLC_DISC_PRIM: sock_hold(sk); @@ -475,7 +474,7 @@ static int llc_exec_conn_trans_actions(struct sock *sk, } /** - * llc_lookup_established - Finds connection for the remote/local sap/mac + * __llc_lookup_established - Finds connection for the remote/local sap/mac * @sap: SAP * @daddr: address of remote LLC (MAC + SAP) * @laddr: address of local LLC (MAC + SAP) @@ -483,14 +482,16 @@ static int llc_exec_conn_trans_actions(struct sock *sk, * Search connection list of the SAP and finds connection using the remote * mac, remote sap, local mac, and local sap. Returns pointer for * connection found, %NULL otherwise. + * Caller has to make sure local_bh is disabled. */ -struct sock *llc_lookup_established(struct llc_sap *sap, struct llc_addr *daddr, - struct llc_addr *laddr) +static struct sock *__llc_lookup_established(struct llc_sap *sap, + struct llc_addr *daddr, + struct llc_addr *laddr) { struct sock *rc; struct hlist_node *node; - read_lock_bh(&sap->sk_list.lock); + read_lock(&sap->sk_list.lock); sk_for_each(rc, node, &sap->sk_list.list) { struct llc_sock *llc = llc_sk(rc); @@ -504,10 +505,22 @@ struct sock *llc_lookup_established(struct llc_sap *sap, struct llc_addr *daddr, } rc = NULL; found: - read_unlock_bh(&sap->sk_list.lock); + read_unlock(&sap->sk_list.lock); return rc; } +struct sock *llc_lookup_established(struct llc_sap *sap, + struct llc_addr *daddr, + struct llc_addr *laddr) +{ + struct sock *sk; + + local_bh_disable(); + sk = __llc_lookup_established(sap, daddr, laddr); + local_bh_enable(); + return sk; +} + /** * llc_lookup_listener - Finds listener for local MAC + SAP * @sap: SAP @@ -516,6 +529,7 @@ found: * Search connection list of the SAP and finds connection listening on * local mac, and local sap. Returns pointer for parent socket found, * %NULL otherwise. + * Caller has to make sure local_bh is disabled. */ static struct sock *llc_lookup_listener(struct llc_sap *sap, struct llc_addr *laddr) @@ -523,7 +537,7 @@ static struct sock *llc_lookup_listener(struct llc_sap *sap, struct sock *rc; struct hlist_node *node; - read_lock_bh(&sap->sk_list.lock); + read_lock(&sap->sk_list.lock); sk_for_each(rc, node, &sap->sk_list.list) { struct llc_sock *llc = llc_sk(rc); @@ -537,10 +551,19 @@ static struct sock *llc_lookup_listener(struct llc_sap *sap, } rc = NULL; found: - read_unlock_bh(&sap->sk_list.lock); + read_unlock(&sap->sk_list.lock); return rc; } +static struct sock *__llc_lookup(struct llc_sap *sap, + struct llc_addr *daddr, + struct llc_addr *laddr) +{ + struct sock *sk = __llc_lookup_established(sap, daddr, laddr); + + return sk ? : llc_lookup_listener(sap, laddr); +} + /** * llc_data_accept_state - designates if in this state data can be sent. * @state: state of connection. @@ -666,15 +689,34 @@ void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk) static int llc_conn_rcv(struct sock* sk, struct sk_buff *skb) { struct llc_conn_state_ev *ev = llc_conn_ev(skb); - struct llc_sock *llc = llc_sk(sk); - if (!llc->dev) - llc->dev = skb->dev; ev->type = LLC_CONN_EV_TYPE_PDU; ev->reason = 0; return llc_conn_state_process(sk, skb); } +static struct sock *llc_create_incoming_sock(struct sock *sk, + struct net_device *dev, + struct llc_addr *saddr, + struct llc_addr *daddr) +{ + struct sock *newsk = llc_sk_alloc(sk->sk_family, GFP_ATOMIC, + sk->sk_prot); + struct llc_sock *newllc, *llc = llc_sk(sk); + + if (!newsk) + goto out; + newllc = llc_sk(newsk); + memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr)); + memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr)); + newllc->dev = dev; + dev_hold(dev); + llc_sap_add_socket(llc->sap, newsk); + llc_sap_hold(llc->sap); +out: + return newsk; +} + void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb) { struct llc_addr saddr, daddr; @@ -685,34 +727,35 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb) llc_pdu_decode_da(skb, daddr.mac); llc_pdu_decode_dsap(skb, &daddr.lsap); - sk = llc_lookup_established(sap, &saddr, &daddr); - if (!sk) { + sk = __llc_lookup(sap, &saddr, &daddr); + if (!sk) + goto drop; + + bh_lock_sock(sk); + /* + * This has to be done here and not at the upper layer ->accept + * method because of the way the PROCOM state machine works: + * it needs to set several state variables (see, for instance, + * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to + * the originator of the new connection, and this state has to be + * in the newly created struct sock private area. -acme + */ + if (unlikely(sk->sk_state == TCP_LISTEN)) { + struct sock *newsk = llc_create_incoming_sock(sk, skb->dev, + &saddr, &daddr); + if (!newsk) + goto drop_unlock; + skb_set_owner_r(skb, newsk); + } else { /* - * Didn't find an active connection; verify if there - * is a listening socket for this llc addr + * Can't be skb_set_owner_r, this will be done at the + * llc_conn_state_process function, later on, when we will use + * skb_queue_rcv_skb to send it to upper layers, this is + * another trick required to cope with how the PROCOM state + * machine works. -acme */ - struct llc_sock *llc; - struct sock *parent = llc_lookup_listener(sap, &daddr); - - if (!parent) { - dprintk("llc_lookup_listener failed!\n"); - goto drop; - } - - sk = llc_sk_alloc(parent->sk_family, GFP_ATOMIC, parent->sk_prot); - if (!sk) { - sock_put(parent); - goto drop; - } - llc = llc_sk(sk); - memcpy(&llc->laddr, &daddr, sizeof(llc->laddr)); - memcpy(&llc->daddr, &saddr, sizeof(llc->daddr)); - llc_sap_add_socket(sap, sk); - sock_hold(sk); - skb_set_owner_r(skb, parent); - sock_put(parent); + skb->sk = sk; } - bh_lock_sock(sk); if (!sock_owned_by_user(sk)) llc_conn_rcv(sk, skb); else { @@ -720,11 +763,16 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb) llc_set_backlog_type(skb, LLC_PACKET); sk_add_backlog(sk, skb); } +out: bh_unlock_sock(sk); sock_put(sk); return; drop: kfree_skb(skb); + return; +drop_unlock: + kfree_skb(skb); + goto out; } #undef LLC_REFCNT_DEBUG -- cgit