linux-toradex.git/net/ipv4/tcp_input.c, branch v3.2.3

tcp: add const qualifiers where possible

2011-10-21T09:22:42+00:00

Adding const qualifiers to pointers can ease code review, and spot some
bugs. It might allow compiler to optimize code further.

For example, is it legal to temporary write a null cksum into tcphdr
in tcp_md5_hash_header() ? I am afraid a sniffer could catch the
temporary null value...

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: remove unused tcp_fin() parameters

2011-10-20T21:44:03+00:00

tcp_fin() only needs socket pointer, we can remove skb and th params.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: use TCP_DEFAULT_INIT_RCVWND in tcp_fixup_rcvbuf()

2011-10-20T20:54:51+00:00

Since commit 356f039822b (TCP: increase default initial receive
window.), we allow sender to send 10 (TCP_DEFAULT_INIT_RCVWND) segments.

Change tcp_fixup_rcvbuf() to reflect this change, even if no real change
is expected, since sysctl_tcp_rmem[1] = 87380 and this value
is bigger than tcp_fixup_rcvbuf() computed rcvmem (~23720)

Note: Since commit 356f039822b limited default window to maximum of
10*1460 and 2*MSS, we use same heuristic in this patch.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: use TCP_INIT_CWND in tcp_fixup_sndbuf()

2011-10-19T20:53:30+00:00

Initial cwnd being 10 (TCP_INIT_CWND) instead of 3, change
tcp_fixup_sndbuf() to get more than 16384 bytes (sysctl_tcp_wmem[1]) in
initial sk_sndbuf

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: more accurate skb truesize

2011-10-13T20:05:07+00:00

skb truesize currently accounts for sk_buff struct and part of skb head.
kmalloc() roundings are also ignored.

Considering that skb_shared_info is larger than sk_buff, its time to
take it into account for better memory accounting.

This patch introduces SKB_TRUESIZE(X) macro to centralize various
assumptions into a single place.

At skb alloc phase, we put skb_shared_info struct at the exact end of
skb head, to allow a better use of memory (lowering number of
reallocations), since kmalloc() gives us power-of-two memory blocks.

Unless SLUB/SLUB debug is active, both skb->head and skb_shared_info are
aligned to cache lines, as before.

Note: This patch might trigger performance regressions because of
misconfigured protocol stacks, hitting per socket or global memory
limits that were previously not reached. But its a necessary step for a
more accurate memory accounting.

Signed-off-by: Eric Dumazet 
CC: Andi Kleen 
CC: Ben Hutchings 
Signed-off-by: David S. Miller

Merge branch 'master' of github.com:davem330/net

2011-10-07T17:38:43+00:00

Conflicts:
	net/batman-adv/soft-interface.c

tcp: properly update lost_cnt_hint during shifting

2011-10-05T03:31:24+00:00

lost_skb_hint is used by tcp_mark_head_lost() to mark the first unhandled skb.
lost_cnt_hint is the number of packets or sacked packets before the lost_skb_hint;
When shifting a skb that is before the lost_skb_hint, if tcp_is_fack() is ture,
the skb has already been counted in the lost_cnt_hint; if tcp_is_fack() is false,
tcp_sacktag_one() will increase the lost_cnt_hint. So tcp_shifted_skb() does not
need to adjust the lost_cnt_hint by itself. When shifting a skb that is equal to
lost_skb_hint, the shifted packets will not be counted by tcp_mark_head_lost().
So tcp_shifted_skb() should adjust the lost_cnt_hint even tcp_is_fack(tp) is true.

Signed-off-by: Zheng Yan 
Signed-off-by: David S. Miller

tcp: rename tcp_skb_cb flags

2011-09-27T17:25:05+00:00

Rename struct tcp_skb_cb "flags" to "tcp_flags" to ease code review and
maintenance.

Its content is a combination of FIN/SYN/RST/PSH/ACK/URG/ECE/CWR flags

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: unalias tcp_skb_cb flags and ip_dsfield

2011-09-27T06:20:08+00:00

struct tcp_skb_cb contains a "flags" field containing either tcp flags
or IP dsfield depending on context (input or output path)

Introduce ip_dsfield to make the difference clear and ease maintenance.
If later we want to save space, we can union flags/ip_dsfield

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: ECN blackhole should not force quickack mode

2011-09-27T04:58:44+00:00

While playing with a new ADSL box at home, I discovered that ECN
blackhole can trigger suboptimal quickack mode on linux : We send one
ACK for each incoming data frame, without any delay and eventual
piggyback.

This is because TCP_ECN_check_ce() considers that if no ECT is seen on a
segment, this is because this segment was a retransmit.

Refine this heuristic and apply it only if we seen ECT in a previous
segment, to detect ECN blackhole at IP level.

Signed-off-by: Eric Dumazet 
CC: Jamal Hadi Salim 
CC: Jerry Chu 
CC: Ilpo Järvinen 
CC: Jim Gettys 
CC: Dave Taht 
Acked-by: Ilpo Järvinen 
Signed-off-by: David S. Miller