TCPCT part 1g: Responder Cookie => Initiator

Parse incoming TCP_COOKIE option(s).

Calculate <SYN,ACK> TCP_COOKIE option.

Send optional <SYN,ACK> data.

This is a significantly revised implementation of an earlier (year-old)
patch that no longer applies cleanly, with permission of the original
author (Adam Langley):

    http://thread.gmane.org/gmane.linux.network/102586

Requires:
   TCPCT part 1a: add request_values parameter for sending SYNACK
   TCPCT part 1b: generate Responder Cookie secret
   TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS
   TCPCT part 1d: define TCP cookie option, extend existing struct's
   TCPCT part 1e: implement socket option TCP_COOKIE_TRANSACTIONS
   TCPCT part 1f: Initiator Cookie => Responder

Signed-off-by: William.Allen.Simpson@gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 6 deletions

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 96852af43ca7..87accec8d097 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -90,13 +90,14 @@ enum tcp_tw_status
 tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
                            const struct tcphdr *th)
 {
-        struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
         struct tcp_options_received tmp_opt;
+        u8 *hash_location;
+        struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
         int paws_reject = 0;
 
         if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
                 tmp_opt.tstamp_ok = 1;
-                tcp_parse_options(skb, &tmp_opt, 1, NULL);
+                tcp_parse_options(skb, &tmp_opt, &hash_location, 1, NULL);
 
                 if (tmp_opt.saw_tstamp) {
                         tmp_opt.ts_recent       = tcptw->tw_ts_recent;
@@ -518,15 +519,16 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
                            struct request_sock *req,
                            struct request_sock **prev)
 {
+        struct tcp_options_received tmp_opt;
+        u8 *hash_location;
+        struct sock *child;
         const struct tcphdr *th = tcp_hdr(skb);
         __be32 flg = tcp_flag_word(th) & (TCP_FLAG_RST|TCP_FLAG_SYN|TCP_FLAG_ACK);
         int paws_reject = 0;
-        struct tcp_options_received tmp_opt;
-        struct sock *child;
 
-        if ((th->doff > (sizeof(struct tcphdr)>>2)) && (req->ts_recent)) {
+        if ((th->doff > (sizeof(*th) >> 2)) && (req->ts_recent)) {
                 tmp_opt.tstamp_ok = 1;
-                tcp_parse_options(skb, &tmp_opt, 1, NULL);
+                tcp_parse_options(skb, &tmp_opt, &hash_location, 1, NULL);
 
                 if (tmp_opt.saw_tstamp) {
                         tmp_opt.ts_recent = req->ts_recent;