diff --git a/include/linux/tcp.h b/include/linux/tcp.h index eaa3113..7fee8a4 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -247,31 +247,38 @@ struct tcp_options_received { sack_ok : 4, /* SACK seen on SYN packet */ snd_wscale : 4, /* Window scaling received from sender */ rcv_wscale : 4; /* Window scaling to send to receiver */ -/* SACKs data */ + u8 cookie_plus:6, /* bytes in authenticator/cookie option */ + cookie_out_never:1, + cookie_in_always:1; u8 num_sacks; /* Number of SACK blocks */ - u16 user_mss; /* mss requested by user in ioctl */ + u16 user_mss; /* mss requested by user in ioctl */ u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ }; static inline void tcp_clear_options(struct tcp_options_received *rx_opt) { - rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; + rx_opt->tstamp_ok = rx_opt->sack_ok = 0; + rx_opt->wscale_ok = rx_opt->snd_wscale = 0; + rx_opt->cookie_plus = 0; } /* This is the max number of SACKS that we'll generate and process. It's safe - * to increse this, although since: + * to increase this, although since: * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) * only four options will fit in a standard TCP header */ #define TCP_NUM_SACKS 4 +struct tcp_cookie_values; +struct tcp_request_sock_ops; + struct tcp_request_sock { struct inet_request_sock req; #ifdef CONFIG_TCP_MD5SIG /* Only used by TCP MD5 Signature so far. */ const struct tcp_request_sock_ops *af_specific; #endif - u32 rcv_isn; - u32 snt_isn; + u32 rcv_isn; + u32 snt_isn; }; static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) @@ -441,6 +448,12 @@ struct tcp_sock { /* TCP MD5 Signature Option information */ struct tcp_md5sig_info *md5sig_info; #endif + + /* When the cookie options are generated and exchanged, then this + * object holds a reference to them (cookie_values->kref). Also + * contains related tcp_cookie_transactions fields. + */ + struct tcp_cookie_values *cookie_values; }; static inline struct tcp_sock *tcp_sk(const struct sock *sk) @@ -459,6 +472,10 @@ struct tcp_timewait_sock { u16 tw_md5_keylen; u8 tw_md5_key[TCP_MD5SIG_MAXKEYLEN]; #endif + /* Few sockets in timewait have cookies; in that case, then this + * object holds a reference to them (tw_cookie_values->kref). + */ + struct tcp_cookie_values *tw_cookie_values; }; static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) diff --git a/include/net/tcp.h b/include/net/tcp.h index 738b65f..f9abd9b 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -164,6 +165,7 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo); #define TCPOPT_SACK 5 /* SACK Block */ #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ +#define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */ /* * TCP option lengths @@ -174,6 +176,10 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo); #define TCPOLEN_SACK_PERM 2 #define TCPOLEN_TIMESTAMP 10 #define TCPOLEN_MD5SIG 18 +#define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */ +#define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */ +#define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN) +#define TCPOLEN_COOKIE_MAX (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX) /* But this is what stacks really send out. */ #define TCPOLEN_TSTAMP_ALIGNED 12 @@ -1482,6 +1488,83 @@ struct tcp_request_sock_ops { extern int tcp_cookie_generator(u32 *bakery); +/** + * struct tcp_cookie_values - each socket needs extra space for the + * cookies, together with (optional) space for any SYN data. + * + * A tcp_sock contains a pointer to the current value, and this is + * cloned to the tcp_timewait_sock. + * + * @cookie_pair: variable data from the option exchange. + * + * @cookie_desired: user specified tcpct_cookie_desired. Zero + * indicates default (sysctl_tcp_cookie_size). + * After cookie sent, remembers size of cookie. + * Range 0, TCP_COOKIE_MIN to TCP_COOKIE_MAX. + * + * @s_data_desired: user specified tcpct_s_data_desired. When the + * constant payload is specified (@s_data_constant), + * holds its length instead. + * Range 0 to TCP_MSS_DESIRED. + * + * @s_data_payload: constant data that is to be included in the + * payload of SYN or SYNACK segments when the + * cookie option is present. + */ +struct tcp_cookie_values { + struct kref kref; + u8 cookie_pair[TCP_COOKIE_PAIR_SIZE]; + u8 cookie_pair_size; + u8 cookie_desired; + u16 s_data_desired:11, + s_data_constant:1, + s_data_in:1, + s_data_out:1, + s_data_unused:2; + u8 s_data_payload[0]; +}; + +static inline void tcp_cookie_values_release(struct kref *kref) +{ + kfree(container_of(kref, struct tcp_cookie_values, kref)); +} + +/* The length of constant payload data. Note that s_data_desired is + * overloaded, depending on s_data_constant: either the length of constant + * data (returned here) or the limit on variable data. + */ +static inline int tcp_s_data_size(const struct tcp_sock *tp) +{ + return (tp->cookie_values != NULL && tp->cookie_values->s_data_constant) + ? tp->cookie_values->s_data_desired + : 0; +} + +/** + * struct tcp_extend_values - tcp_ipv?.c to tcp_output.c workspace. + * + * As tcp_request_sock has already been extended in other places, the + * only remaining method is to pass stack values along as function + * parameters. These parameters are not needed after sending SYNACK. + * + * @cookie_bakery: cryptographic secret and message workspace. + * + * @cookie_plus: bytes in authenticator/cookie option, copied from + * struct tcp_options_received (above). + */ +struct tcp_extend_values { + struct request_values rv; + u32 cookie_bakery[COOKIE_WORKSPACE_WORDS]; + u8 cookie_plus:6, + cookie_out_never:1, + cookie_in_always:1; +}; + +static inline struct tcp_extend_values *tcp_xv(struct request_values *rvp) +{ + return (struct tcp_extend_values *)rvp; +} + extern void tcp_v4_init(void); extern void tcp_init(void); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 397ab8f..2bb7864 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1834,6 +1834,19 @@ static int tcp_v4_init_sock(struct sock *sk) tp->af_specific = &tcp_sock_ipv4_specific; #endif + /* TCP Cookie Transactions */ + if (sysctl_tcp_cookie_size > 0) { + /* Default, cookies without s_data_payload. */ + tp->cookie_values = + kzalloc(sizeof(*tp->cookie_values), + sk->sk_allocation); + if (tp->cookie_values != NULL) + kref_init(&tp->cookie_values->kref); + } + /* Presumed zeroed, in order of appearance: + * cookie_in_always, cookie_out_never, + * s_data_constant, s_data_in, s_data_out + */ sk->sk_sndbuf = sysctl_tcp_wmem[1]; sk->sk_rcvbuf = sysctl_tcp_rmem[1]; @@ -1887,6 +1900,13 @@ void tcp_v4_destroy_sock(struct sock *sk) sk->sk_sndmsg_page = NULL; } + /* TCP Cookie Transactions */ + if (tp->cookie_values != NULL) { + kref_put(&tp->cookie_values->kref, + tcp_cookie_values_release); + tp->cookie_values = NULL; + } + percpu_counter_dec(&tcp_sockets_allocated); } diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 7a42990..53ef6d8 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -389,14 +389,43 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, const struct inet_request_sock *ireq = inet_rsk(req); struct tcp_request_sock *treq = tcp_rsk(req); struct inet_connection_sock *newicsk = inet_csk(newsk); - struct tcp_sock *newtp; + struct tcp_sock *newtp = tcp_sk(newsk); + struct tcp_sock *oldtp = tcp_sk(sk); + struct tcp_cookie_values *oldcvp = oldtp->cookie_values; + + /* TCP Cookie Transactions require space for the cookie pair, + * as it differs for each connection. There is no need to + * copy any s_data_payload stored at the original socket. + * Failure will prevent resuming the connection. + * + * Presumed copied, in order of appearance: + * cookie_in_always, cookie_out_never + */ + if (oldcvp != NULL) { + struct tcp_cookie_values *newcvp = + kzalloc(sizeof(*newtp->cookie_values), + GFP_ATOMIC); + + if (newcvp != NULL) { + kref_init(&newcvp->kref); + newcvp->cookie_desired = + oldcvp->cookie_desired; + newtp->cookie_values = newcvp; + } else { + /* Not Yet Implemented */ + newtp->cookie_values = NULL; + } + } /* Now setup tcp_sock */ - newtp = tcp_sk(newsk); newtp->pred_flags = 0; - newtp->rcv_wup = newtp->copied_seq = newtp->rcv_nxt = treq->rcv_isn + 1; - newtp->snd_sml = newtp->snd_una = newtp->snd_nxt = treq->snt_isn + 1; - newtp->snd_up = treq->snt_isn + 1; + + newtp->rcv_wup = newtp->copied_seq = + newtp->rcv_nxt = treq->rcv_isn + 1; + + newtp->snd_sml = newtp->snd_una = + newtp->snd_nxt = newtp->snd_up = + treq->snt_isn + 1 + tcp_s_data_size(oldtp); tcp_prequeue_init(newtp); @@ -429,8 +458,8 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, tcp_set_ca_state(newsk, TCP_CA_Open); tcp_init_xmit_timers(newsk); skb_queue_head_init(&newtp->out_of_order_queue); - newtp->write_seq = treq->snt_isn + 1; - newtp->pushed_seq = newtp->write_seq; + newtp->write_seq = newtp->pushed_seq = + treq->snt_isn + 1 + tcp_s_data_size(oldtp); newtp->rx_opt.saw_tstamp = 0; @@ -596,7 +625,8 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, * Invalid ACK: reset will be sent by listening socket */ if ((flg & TCP_FLAG_ACK) && - (TCP_SKB_CB(skb)->ack_seq != tcp_rsk(req)->snt_isn + 1)) + (TCP_SKB_CB(skb)->ack_seq != + tcp_rsk(req)->snt_isn + 1 + tcp_s_data_size(tcp_sk(sk)))) return sk; /* Also, it would be not so bad idea to check rcv_tsecr, which diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 3e327bc..973096a 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1865,6 +1865,19 @@ static int tcp_v6_init_sock(struct sock *sk) tp->af_specific = &tcp_sock_ipv6_specific; #endif + /* TCP Cookie Transactions */ + if (sysctl_tcp_cookie_size > 0) { + /* Default, cookies without s_data_payload. */ + tp->cookie_values = + kzalloc(sizeof(*tp->cookie_values), + sk->sk_allocation); + if (tp->cookie_values != NULL) + kref_init(&tp->cookie_values->kref); + } + /* Presumed zeroed, in order of appearance: + * cookie_in_always, cookie_out_never, + * s_data_constant, s_data_in, s_data_out + */ sk->sk_sndbuf = sysctl_tcp_wmem[1]; sk->sk_rcvbuf = sysctl_tcp_rmem[1];