diff --git a/include/linux/tcp.h b/include/linux/tcp.h index eaa3113..6c5ff66 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..3a4c840 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 +1488,72 @@ struct tcp_request_sock_ops { extern int tcp_cookie_generator(u32 *bakery); +/** + * 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; +} + +/* 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. + */ +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); -- 1.6.3.3