From de68b039e970c1e55850818fb1bcd49f52dc02e8 Mon Sep 17 00:00:00 2001 From: Tom Parkin Date: Thu, 3 Sep 2020 09:54:50 +0100 Subject: l2tp: capture more tx errors in data plane stats l2tp_xmit_skb has a number of failure paths which are not reflected in the tunnel and session statistics because the stats are updated by l2tp_xmit_core. Hence any errors occurring before l2tp_xmit_core is called are missed from the statistics. Refactor the transmit path slightly to capture all error paths. l2tp_xmit_skb now leaves all the actual work of transmission to l2tp_xmit_core, and updates the statistics based on l2tp_xmit_core's return code. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller --- net/l2tp/l2tp_core.c | 71 +++++++++++++++++++++++++++------------------------- 1 file changed, 37 insertions(+), 34 deletions(-) (limited to 'net/l2tp') diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index da66a6ed8993..d2672df7e65a 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -985,56 +985,39 @@ static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) return bufp - optr; } -static void l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, struct flowi *fl) +/* Queue the packet to IP for output: tunnel socket lock must be held */ +static int l2tp_xmit_queue(struct l2tp_tunnel *tunnel, struct sk_buff *skb, struct flowi *fl) { - struct l2tp_tunnel *tunnel = session->tunnel; - unsigned int len = skb->len; - int error; + int err; - /* Queue the packet to IP for output */ skb->ignore_df = 1; skb_dst_drop(skb); #if IS_ENABLED(CONFIG_IPV6) if (l2tp_sk_is_v6(tunnel->sock)) - error = inet6_csk_xmit(tunnel->sock, skb, NULL); + err = inet6_csk_xmit(tunnel->sock, skb, NULL); else #endif - error = ip_queue_xmit(tunnel->sock, skb, fl); + err = ip_queue_xmit(tunnel->sock, skb, fl); - /* Update stats */ - if (error >= 0) { - atomic_long_inc(&tunnel->stats.tx_packets); - atomic_long_add(len, &tunnel->stats.tx_bytes); - atomic_long_inc(&session->stats.tx_packets); - atomic_long_add(len, &session->stats.tx_bytes); - } else { - atomic_long_inc(&tunnel->stats.tx_errors); - atomic_long_inc(&session->stats.tx_errors); - } + return err >= 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP; } -/* If caller requires the skb to have a ppp header, the header must be - * inserted in the skb data before calling this function. - */ -int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) +static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb) { - int data_len = skb->len; struct l2tp_tunnel *tunnel = session->tunnel; + unsigned int data_len = skb->len; struct sock *sk = tunnel->sock; - struct flowi *fl; - struct udphdr *uh; - struct inet_sock *inet; - int headroom; - int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; - int udp_len; + int headroom, uhlen, udp_len; int ret = NET_XMIT_SUCCESS; + struct inet_sock *inet; + struct udphdr *uh; /* Check that there's enough headroom in the skb to insert IP, * UDP and L2TP headers. If not enough, expand it to * make room. Adjust truesize. */ - headroom = NET_SKB_PAD + sizeof(struct iphdr) + - uhlen + session->hdr_len; + uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(*uh) : 0; + headroom = NET_SKB_PAD + sizeof(struct iphdr) + uhlen + session->hdr_len; if (skb_cow_head(skb, headroom)) { kfree_skb(skb); return NET_XMIT_DROP; @@ -1048,8 +1031,7 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) /* Reset skb netfilter state */ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); - IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | - IPSKB_REROUTED); + IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED); nf_reset_ct(skb); bh_lock_sock(sk); @@ -1069,7 +1051,6 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) } inet = inet_sk(sk); - fl = &inet->cork.fl; switch (tunnel->encap) { case L2TP_ENCAPTYPE_UDP: /* Setup UDP header */ @@ -1097,12 +1078,34 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) break; } - l2tp_xmit_core(session, skb, fl); + ret = l2tp_xmit_queue(tunnel, skb, &inet->cork.fl); + out_unlock: bh_unlock_sock(sk); return ret; } + +/* If caller requires the skb to have a ppp header, the header must be + * inserted in the skb data before calling this function. + */ +int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) +{ + unsigned int len = skb->len; + int ret; + + ret = l2tp_xmit_core(session, skb); + if (ret == NET_XMIT_SUCCESS) { + atomic_long_inc(&session->tunnel->stats.tx_packets); + atomic_long_add(len, &session->tunnel->stats.tx_bytes); + atomic_long_inc(&session->stats.tx_packets); + atomic_long_add(len, &session->stats.tx_bytes); + } else { + atomic_long_inc(&session->tunnel->stats.tx_errors); + atomic_long_inc(&session->stats.tx_errors); + } + return ret; +} EXPORT_SYMBOL_GPL(l2tp_xmit_skb); /***************************************************************************** -- cgit