diff options
Diffstat (limited to 'net/ipv4/syncookies.c')
| -rw-r--r-- | net/ipv4/syncookies.c | 58 |
1 files changed, 29 insertions, 29 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 6b19530..33016cc 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -2,16 +2,16 @@ * Syncookies implementation for the Linux kernel * * Copyright (C) 1997 Andi Kleen - * Based on ideas by D.J.Bernstein and Eric Schenk. + * Based on ideas by D.J.Bernstein and Eric Schenk. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. - * + * * $Id: syncookies.c,v 1.18 2002/02/01 22:01:04 davem Exp $ * - * Missing: IPv6 support. + * Missing: IPv6 support. */ #include <linux/tcp.h> @@ -57,7 +57,7 @@ static __u32 secure_tcp_syn_cookie(__be32 saddr, __be32 daddr, __be16 sport, /* * Compute the secure sequence number. * The output should be: - * HASH(sec1,saddr,sport,daddr,dport,sec1) + sseq + (count * 2^24) + * HASH(sec1,saddr,sport,daddr,dport,sec1) + sseq + (count * 2^24) * + (HASH(sec2,saddr,sport,daddr,dport,count,sec2) % 2^24). * Where sseq is their sequence number and count increases every * minute by 1. @@ -99,17 +99,17 @@ static __u32 check_tcp_syn_cookie(__u32 cookie, __be32 saddr, __be32 daddr, & COOKIEMASK; /* Leaving the data behind */ } -/* +/* * This table has to be sorted and terminated with (__u16)-1. * XXX generate a better table. * Unresolved Issues: HIPPI with a 64k MSS is not well supported. */ static __u16 const msstab[] = { 64 - 1, - 256 - 1, + 256 - 1, 512 - 1, 536 - 1, - 1024 - 1, + 1024 - 1, 1440 - 1, 1460 - 1, 4312 - 1, @@ -128,7 +128,7 @@ __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mssp) int mssind; const __u16 mss = *mssp; - + tp->last_synq_overflow = jiffies; /* XXX sort msstab[] by probability? Binary search? */ @@ -144,23 +144,23 @@ __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mssp) jiffies / (HZ * 60), mssind); } -/* +/* * This (misnamed) value is the age of syncookie which is permitted. * Its ideal value should be dependent on TCP_TIMEOUT_INIT and * sysctl_tcp_retries1. It's a rather complicated formula (exponential * backoff) to compute at runtime so it's currently hardcoded here. */ #define COUNTER_TRIES 4 -/* - * Check if a ack sequence number is a valid syncookie. +/* + * Check if a ack sequence number is a valid syncookie. * Return the decoded mss if it is, or 0 if not. */ static inline int cookie_check(struct sk_buff *skb, __u32 cookie) { - __u32 seq; + __u32 seq; __u32 mssind; - seq = ntohl(skb->h.th->seq)-1; + seq = ntohl(skb->h.th->seq)-1; mssind = check_tcp_syn_cookie(cookie, skb->nh.iph->saddr, skb->nh.iph->daddr, skb->h.th->source, skb->h.th->dest, @@ -191,19 +191,19 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, struct inet_request_sock *ireq; struct tcp_request_sock *treq; struct tcp_sock *tp = tcp_sk(sk); - __u32 cookie = ntohl(skb->h.th->ack_seq) - 1; + __u32 cookie = ntohl(skb->h.th->ack_seq) - 1; struct sock *ret = sk; - struct request_sock *req; - int mss; - struct rtable *rt; + struct request_sock *req; + int mss; + struct rtable *rt; __u8 rcv_wscale; if (!sysctl_tcp_syncookies || !skb->h.th->ack) goto out; - if (time_after(jiffies, tp->last_synq_overflow + TCP_TIMEOUT_INIT) || + if (time_after(jiffies, tp->last_synq_overflow + TCP_TIMEOUT_INIT) || (mss = cookie_check(skb, cookie)) == 0) { - NET_INC_STATS_BH(LINUX_MIB_SYNCOOKIESFAILED); + NET_INC_STATS_BH(LINUX_MIB_SYNCOOKIESFAILED); goto out; } @@ -221,9 +221,9 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, ireq = inet_rsk(req); treq = tcp_rsk(req); treq->rcv_isn = ntohl(skb->h.th->seq) - 1; - treq->snt_isn = cookie; + treq->snt_isn = cookie; req->mss = mss; - ireq->rmt_port = skb->h.th->source; + ireq->rmt_port = skb->h.th->source; ireq->loc_addr = skb->nh.iph->daddr; ireq->rmt_addr = skb->nh.iph->saddr; ireq->opt = NULL; @@ -242,15 +242,15 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, } ireq->snd_wscale = ireq->rcv_wscale = ireq->tstamp_ok = 0; - ireq->wscale_ok = ireq->sack_ok = 0; - req->expires = 0UL; - req->retrans = 0; - + ireq->wscale_ok = ireq->sack_ok = 0; + req->expires = 0UL; + req->retrans = 0; + /* * We need to lookup the route here to get at the correct * window size. We should better make sure that the window size * hasn't changed since we received the original syn, but I see - * no easy way to do this. + * no easy way to do this. */ { struct flowi fl = { .nl_u = { .ip4_u = @@ -266,17 +266,17 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, security_req_classify_flow(req, &fl); if (ip_route_output_key(&rt, &fl)) { reqsk_free(req); - goto out; + goto out; } } /* Try to redo what tcp_v4_send_synack did. */ req->window_clamp = dst_metric(&rt->u.dst, RTAX_WINDOW); tcp_select_initial_window(tcp_full_space(sk), req->mss, - &req->rcv_wnd, &req->window_clamp, + &req->rcv_wnd, &req->window_clamp, 0, &rcv_wscale); /* BTW win scale with syncookies is 0 by definition */ - ireq->rcv_wscale = rcv_wscale; + ireq->rcv_wscale = rcv_wscale; ret = get_cookie_sock(sk, skb, req, &rt->u.dst); out: return ret; |
