diff options
| -rw-r--r-- | include/linux/if_packet.h | 2 | ||||
| -rw-r--r-- | net/packet/af_packet.c | 33 |
2 files changed, 35 insertions, 0 deletions
diff --git a/include/linux/if_packet.h b/include/linux/if_packet.h index dea7d6b..e5d200f 100644 --- a/include/linux/if_packet.h +++ b/include/linux/if_packet.h @@ -48,11 +48,13 @@ struct sockaddr_ll #define PACKET_RESERVE 12 #define PACKET_TX_RING 13 #define PACKET_LOSS 14 +#define PACKET_GAPDATA 15 struct tpacket_stats { unsigned int tp_packets; unsigned int tp_drops; + unsigned int tp_gap; }; struct tpacket_auxdata diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index d7ecca0..d398a9b 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -524,6 +524,31 @@ static inline unsigned int run_filter(struct sk_buff *skb, struct sock *sk, } /* + * If we've lost frames since the last time we queued one to the + * sk_receive_queue, we need to record it here. + * This must be called under the protection of the socket lock + * to prevent racing with other softirqs and user space + */ +static inline void record_packet_gap(struct sk_buff *skb, + struct packet_sock *po) +{ + /* + * We overload the mark field here, since we're about + * to enqueue to a receive queue and no body else will + * use this field at this point + */ + skb->mark = po->stats.tp_gap; + po->stats.tp_gap = 0; + return; + +} + +static inline __u32 check_packet_gap(struct sk_buff *skb) +{ + return skb->mark; +} + +/* This function makes lazy skb cloning in hope that most of packets are discarded by BPF. @@ -626,6 +651,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, spin_lock(&sk->sk_receive_queue.lock); po->stats.tp_packets++; + record_packet_gap(skb, po); __skb_queue_tail(&sk->sk_receive_queue, skb); spin_unlock(&sk->sk_receive_queue.lock); sk->sk_data_ready(sk, skb->len); @@ -634,6 +660,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, drop_n_acct: spin_lock(&sk->sk_receive_queue.lock); po->stats.tp_drops++; + po->stats.tp_gap++; spin_unlock(&sk->sk_receive_queue.lock); drop_n_restore: @@ -811,6 +838,7 @@ drop: ring_is_full: po->stats.tp_drops++; + po->stats.tp_gap++; spin_unlock(&sk->sk_receive_queue.lock); sk->sk_data_ready(sk, 0); @@ -1418,6 +1446,7 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, struct sk_buff *skb; int copied, err; struct sockaddr_ll *sll; + __u32 gap; err = -EINVAL; if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT)) @@ -1496,6 +1525,10 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux); } + gap = check_packet_gap(skb); + if (gap) + put_cmsg(msg, SOL_PACKET, PACKET_GAPDATA, sizeof(__u32), &gap); + /* * Free or return the buffer as appropriate. Again this * hides all the races and re-entrancy issues from us. |
