diff options
author | Christoph Paasch <christoph.paasch@uclouvain.be> | 2013-03-17 08:23:34 +0000 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-03-17 14:35:13 -0400 |
commit | 1a2c6181c4a1922021b4d7df373bba612c3e5f04 (patch) | |
tree | 1346c9b1db83495a98fbcf95f8e521c67fc55cb9 /net/ipv4/tcp_output.c | |
parent | 94d8f2b133c9ff97105adc1233d1a35e16e1e7a6 (diff) | |
download | op-kernel-dev-1a2c6181c4a1922021b4d7df373bba612c3e5f04.zip op-kernel-dev-1a2c6181c4a1922021b4d7df373bba612c3e5f04.tar.gz |
tcp: Remove TCPCT
TCPCT uses option-number 253, reserved for experimental use and should
not be used in production environments.
Further, TCPCT does not fully implement RFC 6013.
As a nice side-effect, removing TCPCT increases TCP's performance for
very short flows:
Doing an apache-benchmark with -c 100 -n 100000, sending HTTP-requests
for files of 1KB size.
before this patch:
average (among 7 runs) of 20845.5 Requests/Second
after:
average (among 7 runs) of 21403.6 Requests/Second
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
-rw-r--r-- | net/ipv4/tcp_output.c | 219 |
1 files changed, 6 insertions, 213 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 8e7742f..ac5871e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -65,9 +65,6 @@ int sysctl_tcp_base_mss __read_mostly = TCP_BASE_MSS; /* By default, RFC2861 behavior. */ int sysctl_tcp_slow_start_after_idle __read_mostly = 1; -int sysctl_tcp_cookie_size __read_mostly = 0; /* TCP_COOKIE_MAX */ -EXPORT_SYMBOL_GPL(sysctl_tcp_cookie_size); - static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, int push_one, gfp_t gfp); @@ -386,7 +383,6 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp) #define OPTION_TS (1 << 1) #define OPTION_MD5 (1 << 2) #define OPTION_WSCALE (1 << 3) -#define OPTION_COOKIE_EXTENSION (1 << 4) #define OPTION_FAST_OPEN_COOKIE (1 << 8) struct tcp_out_options { @@ -400,36 +396,6 @@ struct tcp_out_options { struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */ }; -/* The sysctl int routines are generic, so check consistency here. - */ -static u8 tcp_cookie_size_check(u8 desired) -{ - int cookie_size; - - if (desired > 0) - /* previously specified */ - return desired; - - cookie_size = ACCESS_ONCE(sysctl_tcp_cookie_size); - if (cookie_size <= 0) - /* no default specified */ - return 0; - - if (cookie_size <= TCP_COOKIE_MIN) - /* value too small, specify minimum */ - return TCP_COOKIE_MIN; - - if (cookie_size >= TCP_COOKIE_MAX) - /* value too large, specify maximum */ - return TCP_COOKIE_MAX; - - if (cookie_size & 1) - /* 8-bit multiple, illegal, fix it */ - cookie_size++; - - return (u8)cookie_size; -} - /* Write previously computed TCP options to the packet. * * Beware: Something in the Internet is very sensitive to the ordering of @@ -448,27 +414,9 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp, { u16 options = opts->options; /* mungable copy */ - /* Having both authentication and cookies for security is redundant, - * and there's certainly not enough room. Instead, the cookie-less - * extension variant is proposed. - * - * Consider the pessimal case with authentication. The options - * could look like: - * COOKIE|MD5(20) + MSS(4) + SACK|TS(12) + WSCALE(4) == 40 - */ if (unlikely(OPTION_MD5 & options)) { - if (unlikely(OPTION_COOKIE_EXTENSION & options)) { - *ptr++ = htonl((TCPOPT_COOKIE << 24) | - (TCPOLEN_COOKIE_BASE << 16) | - (TCPOPT_MD5SIG << 8) | - TCPOLEN_MD5SIG); - } else { - *ptr++ = htonl((TCPOPT_NOP << 24) | - (TCPOPT_NOP << 16) | - (TCPOPT_MD5SIG << 8) | - TCPOLEN_MD5SIG); - } - options &= ~OPTION_COOKIE_EXTENSION; + *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | + (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG); /* overload cookie hash location */ opts->hash_location = (__u8 *)ptr; ptr += 4; @@ -497,44 +445,6 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp, *ptr++ = htonl(opts->tsecr); } - /* Specification requires after timestamp, so do it now. - * - * Consider the pessimal case without authentication. The options - * could look like: - * MSS(4) + SACK|TS(12) + COOKIE(20) + WSCALE(4) == 40 - */ - if (unlikely(OPTION_COOKIE_EXTENSION & options)) { - __u8 *cookie_copy = opts->hash_location; - u8 cookie_size = opts->hash_size; - - /* 8-bit multiple handled in tcp_cookie_size_check() above, - * and elsewhere. - */ - if (0x2 & cookie_size) { - __u8 *p = (__u8 *)ptr; - - /* 16-bit multiple */ - *p++ = TCPOPT_COOKIE; - *p++ = TCPOLEN_COOKIE_BASE + cookie_size; - *p++ = *cookie_copy++; - *p++ = *cookie_copy++; - ptr++; - cookie_size -= 2; - } else { - /* 32-bit multiple */ - *ptr++ = htonl(((TCPOPT_NOP << 24) | - (TCPOPT_NOP << 16) | - (TCPOPT_COOKIE << 8) | - TCPOLEN_COOKIE_BASE) + - cookie_size); - } - - if (cookie_size > 0) { - memcpy(ptr, cookie_copy, cookie_size); - ptr += (cookie_size / 4); - } - } - if (unlikely(OPTION_SACK_ADVERTISE & options)) { *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | @@ -593,11 +503,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, struct tcp_md5sig_key **md5) { struct tcp_sock *tp = tcp_sk(sk); - struct tcp_cookie_values *cvp = tp->cookie_values; unsigned int remaining = MAX_TCP_OPTION_SPACE; - u8 cookie_size = (!tp->rx_opt.cookie_out_never && cvp != NULL) ? - tcp_cookie_size_check(cvp->cookie_desired) : - 0; struct tcp_fastopen_request *fastopen = tp->fastopen_req; #ifdef CONFIG_TCP_MD5SIG @@ -649,52 +555,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, tp->syn_fastopen = 1; } } - /* Note that timestamps are required by the specification. - * - * Odd numbers of bytes are prohibited by the specification, ensuring - * that the cookie is 16-bit aligned, and the resulting cookie pair is - * 32-bit aligned. - */ - if (*md5 == NULL && - (OPTION_TS & opts->options) && - cookie_size > 0) { - int need = TCPOLEN_COOKIE_BASE + cookie_size; - - if (0x2 & need) { - /* 32-bit multiple */ - need += 2; /* NOPs */ - - if (need > remaining) { - /* try shrinking cookie to fit */ - cookie_size -= 2; - need -= 4; - } - } - while (need > remaining && TCP_COOKIE_MIN <= cookie_size) { - cookie_size -= 4; - need -= 4; - } - if (TCP_COOKIE_MIN <= cookie_size) { - opts->options |= OPTION_COOKIE_EXTENSION; - opts->hash_location = (__u8 *)&cvp->cookie_pair[0]; - opts->hash_size = cookie_size; - - /* Remember for future incarnations. */ - cvp->cookie_desired = cookie_size; - - if (cvp->cookie_desired != cvp->cookie_pair_size) { - /* Currently use random bytes as a nonce, - * assuming these are completely unpredictable - * by hostile users of the same system. - */ - get_random_bytes(&cvp->cookie_pair[0], - cookie_size); - cvp->cookie_pair_size = cookie_size; - } - remaining -= need; - } - } return MAX_TCP_OPTION_SPACE - remaining; } @@ -704,14 +565,10 @@ static unsigned int tcp_synack_options(struct sock *sk, unsigned int mss, struct sk_buff *skb, struct tcp_out_options *opts, struct tcp_md5sig_key **md5, - struct tcp_extend_values *xvp, struct tcp_fastopen_cookie *foc) { struct inet_request_sock *ireq = inet_rsk(req); unsigned int remaining = MAX_TCP_OPTION_SPACE; - u8 cookie_plus = (xvp != NULL && !xvp->cookie_out_never) ? - xvp->cookie_plus : - 0; #ifdef CONFIG_TCP_MD5SIG *md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req); @@ -759,28 +616,7 @@ static unsigned int tcp_synack_options(struct sock *sk, remaining -= need; } } - /* Similar rationale to tcp_syn_options() applies here, too. - * If the <SYN> options fit, the same options should fit now! - */ - if (*md5 == NULL && - ireq->tstamp_ok && - cookie_plus > TCPOLEN_COOKIE_BASE) { - int need = cookie_plus; /* has TCPOLEN_COOKIE_BASE */ - - if (0x2 & need) { - /* 32-bit multiple */ - need += 2; /* NOPs */ - } - if (need <= remaining) { - opts->options |= OPTION_COOKIE_EXTENSION; - opts->hash_size = cookie_plus - TCPOLEN_COOKIE_BASE; - remaining -= need; - } else { - /* There's no error return, so flag it. */ - xvp->cookie_out_never = 1; /* true */ - opts->hash_size = 0; - } - } + return MAX_TCP_OPTION_SPACE - remaining; } @@ -2802,32 +2638,24 @@ int tcp_send_synack(struct sock *sk) * sk: listener socket * dst: dst entry attached to the SYNACK * req: request_sock pointer - * rvp: request_values pointer * * Allocate one skb and build a SYNACK packet. * @dst is consumed : Caller should not use it again. */ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, struct request_sock *req, - struct request_values *rvp, struct tcp_fastopen_cookie *foc) { struct tcp_out_options opts; - struct tcp_extend_values *xvp = tcp_xv(rvp); struct inet_request_sock *ireq = inet_rsk(req); struct tcp_sock *tp = tcp_sk(sk); - const struct tcp_cookie_values *cvp = tp->cookie_values; struct tcphdr *th; struct sk_buff *skb; struct tcp_md5sig_key *md5; int tcp_header_size; int mss; - int s_data_desired = 0; - if (cvp != NULL && cvp->s_data_constant && cvp->s_data_desired) - s_data_desired = cvp->s_data_desired; - skb = alloc_skb(MAX_TCP_HEADER + 15 + s_data_desired, - sk_gfp_atomic(sk, GFP_ATOMIC)); + skb = alloc_skb(MAX_TCP_HEADER + 15, sk_gfp_atomic(sk, GFP_ATOMIC)); if (unlikely(!skb)) { dst_release(dst); return NULL; @@ -2869,9 +2697,8 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, else #endif TCP_SKB_CB(skb)->when = tcp_time_stamp; - tcp_header_size = tcp_synack_options(sk, req, mss, - skb, &opts, &md5, xvp, foc) - + sizeof(*th); + tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, &md5, + foc) + sizeof(*th); skb_push(skb, tcp_header_size); skb_reset_transport_header(skb); @@ -2889,40 +2716,6 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, tcp_init_nondata_skb(skb, tcp_rsk(req)->snt_isn, TCPHDR_SYN | TCPHDR_ACK); - if (OPTION_COOKIE_EXTENSION & opts.options) { - if (s_data_desired) { - u8 *buf = skb_put(skb, s_data_desired); - - /* copy data directly from the listening socket. */ - memcpy(buf, cvp->s_data_payload, s_data_desired); - TCP_SKB_CB(skb)->end_seq += s_data_desired; - } - - if (opts.hash_size > 0) { - __u32 workspace[SHA_WORKSPACE_WORDS]; - u32 *mess = &xvp->cookie_bakery[COOKIE_DIGEST_WORDS]; - u32 *tail = &mess[COOKIE_MESSAGE_WORDS-1]; - - /* Secret recipe depends on the Timestamp, (future) - * Sequence and Acknowledgment Numbers, Initiator - * Cookie, and others handled by IP variant caller. - */ - *tail-- ^= opts.tsval; - *tail-- ^= tcp_rsk(req)->rcv_isn + 1; - *tail-- ^= TCP_SKB_CB(skb)->seq + 1; - - /* recommended */ - *tail-- ^= (((__force u32)th->dest << 16) | (__force u32)th->source); - *tail-- ^= (u32)(unsigned long)cvp; /* per sockopt */ - - sha_transform((__u32 *)&xvp->cookie_bakery[0], - (char *)mess, - &workspace[0]); - opts.hash_location = - (__u8 *)&xvp->cookie_bakery[0]; - } - } - th->seq = htonl(TCP_SKB_CB(skb)->seq); /* XXX data is queued and acked as is. No buffer/window check */ th->ack_seq = htonl(tcp_rsk(req)->rcv_nxt); |