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udp: fix rx queue len reported by diag and proc interface

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After commit 6b229cf77d ("udp: add batching to udp_rmem_release()")
the sk_rmem_alloc field does not measure exactly anymore the
receive queue length, because we batch the rmem release. The issue
is really apparent only after commit 0d4a6608f6 ("udp: do rmem bulk
free even if the rx sk queue is empty"): the user space can easily
check for an empty socket with not-0 queue length reported by the 'ss'
tool or the procfs interface.

We need to use a custom UDP helper to report the correct queue length,
taking into account the forward allocation deficit.

Reported-by: trevor.francis@46labs.com
Fixes: 6b229cf77d ("UDP: add batching to udp_rmem_release()")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2018-06-08 11:35:40 +02:00 committed by David S. Miller
parent 49c2c3f246
commit 6c206b2009
6 changed files with 21 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
include/net/transp_v6.h
View file

@ -45,8 +45,15 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, struct msghdr *msg,
struct flowi6 *fl6, struct ipcm6_cookie *ipc6,
struct sockcm_cookie *sockc);
void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
__u16 srcp, __u16 destp, int bucket);
void __ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
__u16 srcp, __u16 destp, int rqueue, int bucket);
static inline void
ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp, __u16 srcp,
__u16 destp, int bucket)
{
__ip6_dgram_sock_seq_show(seq, sp, srcp, destp, sk_rmem_alloc_get(sp),
bucket);
}
#define LOOPBACK4_IPV6 cpu_to_be32(0x7f000006)

5
include/net/udp.h
View file

@ -247,6 +247,11 @@ static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
return htons((((u64) hash * (max - min)) >> 32) + min);
}
static inline int udp_rqueue_get(struct sock *sk)
{
return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
}
/* net/ipv4/udp.c */
void udp_destruct_sock(struct sock *sk);
void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);

2
net/ipv4/udp.c
View file

@ -2772,7 +2772,7 @@ static void udp4_format_sock(struct sock *sp, struct seq_file *f,
" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
bucket, src, srcp, dest, destp, sp->sk_state,
sk_wmem_alloc_get(sp),
sk_rmem_alloc_get(sp),
udp_rqueue_get(sp),
0, 0L, 0,
from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
0, sock_i_ino(sp),

2
net/ipv4/udp_diag.c
View file

@ -163,7 +163,7 @@ static int udp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
static void udp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
void *info)
{
r->idiag_rqueue = sk_rmem_alloc_get(sk);
r->idiag_rqueue = udp_rqueue_get(sk);
r->idiag_wqueue = sk_wmem_alloc_get(sk);
}

6
net/ipv6/datagram.c
View file

@ -1019,8 +1019,8 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
}
EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
__u16 srcp, __u16 destp, int bucket)
void __ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
__u16 srcp, __u16 destp, int rqueue, int bucket)
{
const struct in6_addr *dest, *src;
@ -1036,7 +1036,7 @@ void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
dest->s6_addr32[2], dest->s6_addr32[3], destp,
sp->sk_state,
sk_wmem_alloc_get(sp),
sk_rmem_alloc_get(sp),
rqueue,
0, 0L, 0,
from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
0,

3
net/ipv6/udp.c
View file

@ -1523,7 +1523,8 @@ int udp6_seq_show(struct seq_file *seq, void *v)
struct inet_sock *inet = inet_sk(v);
__u16 srcp = ntohs(inet->inet_sport);
__u16 destp = ntohs(inet->inet_dport);
ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
__ip6_dgram_sock_seq_show(seq, v, srcp, destp,
udp_rqueue_get(v), bucket);
}
return 0;
}