diff options
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r-- | include/net/tcp.h | 46 |
1 files changed, 39 insertions, 7 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index fed2a78fb8cb..0e3a88f808c6 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -53,6 +53,8 @@ void tcp_time_wait(struct sock *sk, int state, int timeo); #define MAX_TCP_HEADER (128 + MAX_HEADER) #define MAX_TCP_OPTION_SPACE 40 +#define TCP_MIN_SND_MSS 48 +#define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE) /* * Never offer a window over 32767 without using window scaling. Some @@ -492,19 +494,27 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb); */ static inline void tcp_synq_overflow(const struct sock *sk) { - unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; + unsigned long last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); unsigned long now = jiffies; - if (time_after(now, last_overflow + HZ)) - tcp_sk(sk)->rx_opt.ts_recent_stamp = now; + if (!time_between32(now, last_overflow, last_overflow + HZ)) + WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now); } /* syncookies: no recent synqueue overflow on this listening socket? */ static inline bool tcp_synq_no_recent_overflow(const struct sock *sk) { - unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; + unsigned long last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp); - return time_after(jiffies, last_overflow + TCP_SYNCOOKIE_VALID); + /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID, + * then we're under synflood. However, we have to use + * 'last_overflow - HZ' as lower bound. That's because a concurrent + * tcp_synq_overflow() could update .ts_recent_stamp after we read + * jiffies but before we store .ts_recent_stamp into last_overflow, + * which could lead to rejecting a valid syncookie. + */ + return !time_between32(jiffies, last_overflow - HZ, + last_overflow + TCP_SYNCOOKIE_VALID); } static inline u32 tcp_cookie_time(void) @@ -1510,6 +1520,11 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, void tcp_fastopen_init_key_once(bool publish); #define TCP_FASTOPEN_KEY_LENGTH 16 +static inline void tcp_init_send_head(struct sock *sk) +{ + sk->sk_send_head = NULL; +} + /* Fastopen key context */ struct tcp_fastopen_context { struct crypto_cipher *tfm; @@ -1526,6 +1541,7 @@ static inline void tcp_write_queue_purge(struct sock *sk) sk_wmem_free_skb(sk, skb); sk_mem_reclaim(sk); tcp_clear_all_retrans_hints(tcp_sk(sk)); + tcp_init_send_head(sk); inet_csk(sk)->icsk_backoff = 0; } @@ -1587,9 +1603,25 @@ static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unli tcp_sk(sk)->highest_sack = NULL; } -static inline void tcp_init_send_head(struct sock *sk) +static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) { - sk->sk_send_head = NULL; + struct sk_buff *skb = tcp_write_queue_head(sk); + + if (skb == tcp_send_head(sk)) + skb = NULL; + + return skb; +} + +static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) +{ + struct sk_buff *skb = tcp_send_head(sk); + + /* empty retransmit queue, for example due to zero window */ + if (skb == tcp_write_queue_head(sk)) + return NULL; + + return skb ? tcp_write_queue_prev(sk, skb) : tcp_write_queue_tail(sk); } static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) |