lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 24 Aug 2009 13:40:17 -0400 (EDT) From: Christoph Lameter <cl@...ux-foundation.org> To: Sridhar Samudrala <sri@...ibm.com> cc: Nivedita Singhvi <niv@...ibm.com>, netdev@...r.kernel.org, Eric Dumazet <dada1@...mosbay.com> Subject: Re: UDP multicast packet loss not reported if TX ring overrun? On Mon, 17 Aug 2009, Sridhar Samudrala wrote: > So it is possible that there is some other place in the stack where the packets > are gettting dropped but not counted. Such a deed occurs in ip_push_pending_frames(): /* Netfilter gets whole the not fragmented skb. */ err = ip_local_out(skb); if (err) { if (err > 0) err = inet->recverr ? net_xmit_errno(err) : 0; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ if (err) goto error; } out: ip_cork_release(inet); return err; error: IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); goto out; So if ip_local_out returns NET_XMIT_DROP then its simply going to be replaced by 0. Then we check err again and there is no error!!!! The statistics are only generated if IP_RECVERR is set. Could we move the increment of IPSTATS_MIB_OUTDISCARDS up so that it is incremented regardless of the setting of IP_RECVERR? F.e? Subject: Report TX drops Incrementing of TX drop counters currently does not work if errors from the network stack are suppressed (IP_RECVERR off). Increment the statistics independently of the setting of IP_RECVERR. Signed-off-by: Christoph Lameter <cl@...ux-foundation.org> --- net/ipv4/ip_output.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) Index: linux-2.6/net/ipv4/ip_output.c =================================================================== --- linux-2.6.orig/net/ipv4/ip_output.c 2009-08-24 17:04:27.000000000 +0000 +++ linux-2.6/net/ipv4/ip_output.c 2009-08-24 17:32:05.000000000 +0000 @@ -1300,20 +1300,21 @@ int ip_push_pending_frames(struct sock * /* Netfilter gets whole the not fragmented skb. */ err = ip_local_out(skb); - if (err) { - if (err > 0) - err = inet->recverr ? net_xmit_errno(err) : 0; - if (err) - goto error; + if (err > 0) { + /* The packet was dropped by the network subsystem */ + IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); + + /* + * Errors are not passed on if the socket + * does not process errors (see IP_RECVERR). + * net_xmit_errno filters NET_XMIT_CN. + */ + err = inet->recverr ? net_xmit_errno(err) : 0; } out: ip_cork_release(inet); return err; - -error: - IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS); - goto out; } /* -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists