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udp: remove headers from UDP packets before queueing
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Remove UDP transport headers before queueing packets for reception.
This change simplifies a follow-up patch to add MSG_PEEK support.

Signed-off-by: Sam Kumar <samanthakumar@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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samanthakumar authored and David S. Miller committed Apr 5, 2016
1 parent b9bb53f commit e6afc8a
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Showing 5 changed files with 41 additions and 20 deletions.
1 change: 1 addition & 0 deletions include/net/sock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1864,6 +1864,7 @@ void sk_reset_timer(struct sock *sk, struct timer_list *timer,

void sk_stop_timer(struct sock *sk, struct timer_list *timer);

int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);

int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
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9 changes: 9 additions & 0 deletions include/net/udp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -158,6 +158,15 @@ static inline __sum16 udp_v4_check(int len, __be32 saddr,
void udp_set_csum(bool nocheck, struct sk_buff *skb,
__be32 saddr, __be32 daddr, int len);

static inline void udp_csum_pull_header(struct sk_buff *skb)
{
if (skb->ip_summed == CHECKSUM_NONE)
skb->csum = csum_partial(udp_hdr(skb), sizeof(struct udphdr),
skb->csum);
skb_pull_rcsum(skb, sizeof(struct udphdr));
UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
}

struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
struct udphdr *uh);
int udp_gro_complete(struct sk_buff *skb, int nhoff);
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19 changes: 13 additions & 6 deletions net/core/sock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -402,9 +402,8 @@ static void sock_disable_timestamp(struct sock *sk, unsigned long flags)
}


int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int err;
unsigned long flags;
struct sk_buff_head *list = &sk->sk_receive_queue;

Expand All @@ -414,10 +413,6 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
return -ENOMEM;
}

err = sk_filter(sk, skb);
if (err)
return err;

if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
atomic_inc(&sk->sk_drops);
return -ENOBUFS;
Expand All @@ -440,6 +435,18 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
sk->sk_data_ready(sk);
return 0;
}
EXPORT_SYMBOL(__sock_queue_rcv_skb);

int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int err;

err = sk_filter(sk, skb);
if (err)
return err;

return __sock_queue_rcv_skb(sk, skb);
}
EXPORT_SYMBOL(sock_queue_rcv_skb);

int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested)
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20 changes: 11 additions & 9 deletions net/ipv4/udp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1309,7 +1309,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
if (!skb)
goto out;

ulen = skb->len - sizeof(struct udphdr);
ulen = skb->len;
copied = len;
if (copied > ulen)
copied = ulen;
Expand All @@ -1329,11 +1329,9 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
}

if (checksum_valid || skb_csum_unnecessary(skb))
err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
msg, copied);
err = skb_copy_datagram_msg(skb, 0, msg, copied);
else {
err = skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr),
msg);
err = skb_copy_and_csum_datagram_msg(skb, 0, msg);

if (err == -EINVAL)
goto csum_copy_err;
Expand Down Expand Up @@ -1500,7 +1498,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
sk_incoming_cpu_update(sk);
}

rc = sock_queue_rcv_skb(sk, skb);
rc = __sock_queue_rcv_skb(sk, skb);
if (rc < 0) {
int is_udplite = IS_UDPLITE(sk);

Expand Down Expand Up @@ -1616,10 +1614,14 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
}
}

if (rcu_access_pointer(sk->sk_filter) &&
udp_lib_checksum_complete(skb))
goto csum_error;
if (rcu_access_pointer(sk->sk_filter)) {
if (udp_lib_checksum_complete(skb))
goto csum_error;
if (sk_filter(sk, skb))
goto drop;
}

udp_csum_pull_header(skb);
if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
is_udplite);
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12 changes: 7 additions & 5 deletions net/ipv6/udp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -376,7 +376,7 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
if (!skb)
goto out;

ulen = skb->len - sizeof(struct udphdr);
ulen = skb->len;
copied = len;
if (copied > ulen)
copied = ulen;
Expand All @@ -398,10 +398,9 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
}

if (checksum_valid || skb_csum_unnecessary(skb))
err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
msg, copied);
err = skb_copy_datagram_msg(skb, 0, msg, copied);
else {
err = skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg);
err = skb_copy_and_csum_datagram_msg(skb, 0, msg);
if (err == -EINVAL)
goto csum_copy_err;
}
Expand Down Expand Up @@ -554,7 +553,7 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
sk_incoming_cpu_update(sk);
}

rc = sock_queue_rcv_skb(sk, skb);
rc = __sock_queue_rcv_skb(sk, skb);
if (rc < 0) {
int is_udplite = IS_UDPLITE(sk);

Expand Down Expand Up @@ -648,8 +647,11 @@ int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
if (rcu_access_pointer(sk->sk_filter)) {
if (udp_lib_checksum_complete(skb))
goto csum_error;
if (sk_filter(sk, skb))
goto drop;
}

udp_csum_pull_header(skb);
if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
UDP6_INC_STATS_BH(sock_net(sk),
UDP_MIB_RCVBUFERRORS, is_udplite);
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