Commit 6c206b20 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

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



After commit 6b229cf7 ("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 0d4a6608 ("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: default avatar <trevor.francis@46labs.com>
Fixes: 6b229cf7 ("UDP: add batching to udp_rmem_release()")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 49c2c3f2

include/net/transp_v6.h

+9 −2
Original line number Diff line number Diff line
@@ -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)

include/net/udp.h

+5 −0
Original line number Diff line number Diff line
@@ -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);

net/ipv4/udp.c

+1 −1
Original line number Diff line number Diff line
@@ -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),

net/ipv4/udp_diag.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

net/ipv6/datagram.c

+3 −3
Original line number Diff line number Diff line
@@ -1019,8 +1019,8 @@ exit_f: 
}

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,

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