tcp: options clean up
This should fix the following bugs: * Connections with MD5 signatures produce invalid packets whenever SACK options are included * MD5 signatures are counted twice in the MSS calculations Behaviour changes: * A SYN with MD5 + SACK + TS elicits a SYNACK with MD5 + SACK This is because we can't fit any SACK blocks in a packet with MD5 + TS options. There was discussion about disabling SACK rather than TS in order to fit in better with old, buggy kernels, but that was deemed to be unnecessary. * SYNs with MD5 don't include a TS option See above. Additionally, it removes a bunch of duplicated logic for calculating options, which should help avoid these sort of issues in the future. Signed-off-by: Adam Langley <agl@imperialviolet.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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committed by
David S. Miller

parent
49a72dfb88
commit
33ad798c92
@@ -50,6 +50,7 @@ extern atomic_t tcp_orphan_count;
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extern void tcp_time_wait(struct sock *sk, int state, int timeo);
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#define MAX_TCP_HEADER (128 + MAX_HEADER)
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#define MAX_TCP_OPTION_SPACE 40
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/*
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* Never offer a window over 32767 without using window scaling. Some
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@@ -184,6 +185,7 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
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#define TCPOLEN_SACK_BASE_ALIGNED 4
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#define TCPOLEN_SACK_PERBLOCK 8
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#define TCPOLEN_MD5SIG_ALIGNED 20
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#define TCPOLEN_MSS_ALIGNED 4
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/* Flags in tp->nonagle */
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#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
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