diff options
| author |   Florian Westphal <fw@strlen.de> | 2021-04-01 16:19:44 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2021-04-02 14:21:50 -0700 |
| commit | dc87efdb1a5cd46134a9d490480160e303bc6eef (patch) | |
| tree | 57040990350f1bf27ddecf5f015c445fcf4b888f /net/ipv4/tcp_ipv4.c | |
| parent | mptcp: remove unneeded check on first subflow (diff) | |
| download | linux-dev-dc87efdb1a5cd46134a9d490480160e303bc6eef.tar.xz linux-dev-dc87efdb1a5cd46134a9d490480160e303bc6eef.zip | |
mptcp: add mptcp reset option support
The MPTCP reset option allows to carry a mptcp-specific error code that
provides more information on the nature of a connection reset.
Reset option data received gets stored in the subflow context so it can
be sent to userspace via the 'subflow closed' netlink event.
When a subflow is closed, the desired error code that should be sent to
the peer is also placed in the subflow context structure.
If a reset is sent before subflow establishment could complete, e.g. on
HMAC failure during an MP_JOIN operation, the mptcp skb extension is
used to store the reset information.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index dfc6d1c0e710..312184cead57 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -655,14 +655,18 @@ EXPORT_SYMBOL(tcp_v4_send_check); * Exception: precedence violation. We do not implement it in any case. */ +#ifdef CONFIG_TCP_MD5SIG +#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED +#else +#define OPTION_BYTES sizeof(__be32) +#endif + static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) { const struct tcphdr *th = tcp_hdr(skb); struct { struct tcphdr th; -#ifdef CONFIG_TCP_MD5SIG - __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)]; -#endif + __be32 opt[OPTION_BYTES / sizeof(__be32)]; } rep; struct ip_reply_arg arg; #ifdef CONFIG_TCP_MD5SIG @@ -770,6 +774,17 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) ip_hdr(skb)->daddr, &rep.th); } #endif + /* Can't co-exist with TCPMD5, hence check rep.opt[0] */ + if (rep.opt[0] == 0) { + __be32 mrst = mptcp_reset_option(skb); + + if (mrst) { + rep.opt[0] = mrst; + arg.iov[0].iov_len += sizeof(mrst); + rep.th.doff = arg.iov[0].iov_len / 4; + } + } + arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, ip_hdr(skb)->saddr, /* XXX */ arg.iov[0].iov_len, IPPROTO_TCP, 0); |