EXPORT_SYMBOL(sysctl_tcp_ecn);
int sysctl_tcp_dsack __read_mostly = 1;
int sysctl_tcp_app_win __read_mostly = 31;
-int sysctl_tcp_adv_win_scale __read_mostly = 2;
+int sysctl_tcp_adv_win_scale __read_mostly = 1;
EXPORT_SYMBOL(sysctl_tcp_adv_win_scale);
+/* rfc5961 challenge ack rate limiting */
+int sysctl_tcp_challenge_ack_limit = 1000;
+
int sysctl_tcp_stdurg __read_mostly;
int sysctl_tcp_rfc1337 __read_mostly;
int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
#define FLAG_DSACKING_ACK 0x800 /* SACK blocks contained D-SACK info */
#define FLAG_NONHEAD_RETRANS_ACKED 0x1000 /* Non-head rexmitted data was ACKed */
#define FLAG_SACK_RENEGING 0x2000 /* snd_una advanced to a sacked seq */
+#define FLAG_UPDATE_TS_RECENT 0x4000 /* tcp_replace_ts_recent() */
#define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED)
#define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
incr = __tcp_grow_window(sk, skb);
if (incr) {
+ incr = max_t(int, incr, 2 * skb->len);
tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr,
tp->window_clamp);
inet_csk(sk)->icsk_ack.quick |= 1;
if (!win_dep) {
m -= (new_sample >> 3);
new_sample += m;
- } else if (m < new_sample)
- new_sample = m << 3;
+ } else {
+ m <<= 3;
+ if (m < new_sample)
+ new_sample = m;
+ }
} else {
/* No previous measure. */
new_sample = m << 3;
*/
if (pkt_len > mss) {
unsigned int new_len = (pkt_len / mss) * mss;
- if (!in_sack && new_len < pkt_len) {
+ if (!in_sack && new_len < pkt_len)
new_len += mss;
- if (new_len > skb->len)
- return 0;
- }
pkt_len = new_len;
}
+
+ if (pkt_len >= skb->len && !in_sack)
+ return 0;
+
err = tcp_fragment(sk, skb, pkt_len, mss);
if (err < 0)
return err;
return in_sack;
}
-static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
- struct tcp_sacktag_state *state,
+/* Mark the given newly-SACKed range as such, adjusting counters and hints. */
+static u8 tcp_sacktag_one(struct sock *sk,
+ struct tcp_sacktag_state *state, u8 sacked,
+ u32 start_seq, u32 end_seq,
int dup_sack, int pcount)
{
struct tcp_sock *tp = tcp_sk(sk);
- u8 sacked = TCP_SKB_CB(skb)->sacked;
int fack_count = state->fack_count;
/* Account D-SACK for retransmitted packet. */
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans &&
- after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
+ after(end_seq, tp->undo_marker))
tp->undo_retrans--;
if (sacked & TCPCB_SACKED_ACKED)
state->reord = min(fack_count, state->reord);
}
/* Nothing to do; acked frame is about to be dropped (was ACKed). */
- if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
+ if (!after(end_seq, tp->snd_una))
return sacked;
if (!(sacked & TCPCB_SACKED_ACKED)) {
/* New sack for not retransmitted frame,
* which was in hole. It is reordering.
*/
- if (before(TCP_SKB_CB(skb)->seq,
+ if (before(start_seq,
tcp_highest_sack_seq(tp)))
state->reord = min(fack_count,
state->reord);
/* SACK enhanced F-RTO (RFC4138; Appendix B) */
- if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
+ if (!after(end_seq, tp->frto_highmark))
state->flag |= FLAG_ONLY_ORIG_SACKED;
}
/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
- before(TCP_SKB_CB(skb)->seq,
- TCP_SKB_CB(tp->lost_skb_hint)->seq))
+ before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq))
tp->lost_cnt_hint += pcount;
if (fack_count > tp->fackets_out)
return sacked;
}
+/* Shift newly-SACKed bytes from this skb to the immediately previous
+ * already-SACKed sk_buff. Mark the newly-SACKed bytes as such.
+ */
static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
struct tcp_sacktag_state *state,
unsigned int pcount, int shifted, int mss,
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *prev = tcp_write_queue_prev(sk, skb);
+ u32 start_seq = TCP_SKB_CB(skb)->seq; /* start of newly-SACKed */
+ u32 end_seq = start_seq + shifted; /* end of newly-SACKed */
BUG_ON(!pcount);
+ /* Adjust counters and hints for the newly sacked sequence
+ * range but discard the return value since prev is already
+ * marked. We must tag the range first because the seq
+ * advancement below implicitly advances
+ * tcp_highest_sack_seq() when skb is highest_sack.
+ */
+ tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
+ start_seq, end_seq, dup_sack, pcount);
+
if (skb == tp->lost_skb_hint)
tp->lost_cnt_hint += pcount;
TCP_SKB_CB(skb)->seq += shifted;
skb_shinfo(prev)->gso_segs += pcount;
- BUG_ON(skb_shinfo(skb)->gso_segs < pcount);
+ WARN_ON_ONCE(tcp_skb_pcount(skb) < pcount);
skb_shinfo(skb)->gso_segs -= pcount;
/* When we're adding to gso_segs == 1, gso_size will be zero,
skb_shinfo(skb)->gso_type = 0;
}
- /* We discard results */
- tcp_sacktag_one(skb, sk, state, dup_sack, pcount);
-
/* Difference in this won't matter, both ACKed by the same cumul. ACK */
TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
tp->lost_cnt_hint -= tcp_skb_pcount(prev);
}
- TCP_SKB_CB(skb)->tcp_flags |= TCP_SKB_CB(prev)->tcp_flags;
+ TCP_SKB_CB(prev)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+ TCP_SKB_CB(prev)->end_seq++;
+
if (skb == tcp_highest_sack(sk))
tcp_advance_highest_sack(sk, skb);
return !skb_headlen(skb) && skb_is_nonlinear(skb);
}
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from,
+ int pcount, int shiftlen)
+{
+ /* TCP min gso_size is 8 bytes (TCP_MIN_GSO_SIZE)
+ * Since TCP_SKB_CB(skb)->tcp_gso_segs is 16 bits, we need
+ * to make sure not storing more than 65535 * 8 bytes per skb,
+ * even if current MSS is bigger.
+ */
+ if (unlikely(to->len + shiftlen >= 65535 * TCP_MIN_GSO_SIZE))
+ return 0;
+ if (unlikely(tcp_skb_pcount(to) + pcount > 65535))
+ return 0;
+ return skb_shift(to, from, shiftlen);
+}
+
/* Try collapsing SACK blocks spanning across multiple skbs to a single
* skb.
*/
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *prev;
int mss;
+ int next_pcount;
int pcount = 0;
int len;
int in_sack;
}
}
- if (!skb_shift(prev, skb, len))
+ /* tcp_sacktag_one() won't SACK-tag ranges below snd_una */
+ if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
+ goto fallback;
+
+ if (!tcp_skb_shift(prev, skb, pcount, len))
goto fallback;
if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
goto out;
goto out;
len = skb->len;
- if (skb_shift(prev, skb, len)) {
- pcount += tcp_skb_pcount(skb);
- tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);
+ next_pcount = tcp_skb_pcount(skb);
+ if (tcp_skb_shift(prev, skb, next_pcount, len)) {
+ pcount += next_pcount;
+ tcp_shifted_skb(sk, skb, state, next_pcount, len, mss, 0);
}
out:
break;
if (in_sack) {
- TCP_SKB_CB(skb)->sacked = tcp_sacktag_one(skb, sk,
- state,
- dup_sack,
- tcp_skb_pcount(skb));
+ TCP_SKB_CB(skb)->sacked =
+ tcp_sacktag_one(sk,
+ state,
+ TCP_SKB_CB(skb)->sacked,
+ TCP_SKB_CB(skb)->seq,
+ TCP_SKB_CB(skb)->end_seq,
+ dup_sack,
+ tcp_skb_pcount(skb));
if (!before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(tp)))
if (tcp_is_reno(tp))
tcp_reset_reno_sack(tp);
- if (!how) {
- /* Push undo marker, if it was plain RTO and nothing
- * was retransmitted. */
- tp->undo_marker = tp->snd_una;
- } else {
+ tp->undo_marker = tp->snd_una;
+ if (how) {
tp->sacked_out = 0;
tp->fackets_out = 0;
}
if (cnt > packets) {
if ((tcp_is_sack(tp) && !tcp_is_fack(tp)) ||
+ (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
(oldcnt >= packets))
break;
/* Do not moderate cwnd if it's already undone in cwr or recovery. */
if (tp->undo_marker) {
- if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR)
+ if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR) {
tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
- else /* PRR */
+ tp->snd_cwnd_stamp = tcp_time_stamp;
+ } else if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH) {
+ /* PRR algorithm. */
tp->snd_cwnd = tp->snd_ssthresh;
- tp->snd_cwnd_stamp = tcp_time_stamp;
+ tp->snd_cwnd_stamp = tcp_time_stamp;
+ }
}
tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR);
}
int delta;
/* Non-retransmitted hole got filled? That's reordering */
- if (reord < prior_fackets)
+ if (reord < prior_fackets && reord <= tp->fackets_out)
tcp_update_reordering(sk, tp->fackets_out - reord, 0);
delta = tcp_is_fack(tp) ? pkts_acked :
}
} else {
if (!(flag & FLAG_DATA_ACKED) && (tp->frto_counter == 1)) {
+ if (!tcp_packets_in_flight(tp)) {
+ tcp_enter_frto_loss(sk, 2, flag);
+ return true;
+ }
+
/* Prevent sending of new data. */
tp->snd_cwnd = min(tp->snd_cwnd,
tcp_packets_in_flight(tp));
return 0;
}
+/* RFC 5961 7 [ACK Throttling] */
+static void tcp_send_challenge_ack(struct sock *sk)
+{
+ /* unprotected vars, we dont care of overwrites */
+ static u32 challenge_timestamp;
+ static unsigned int challenge_count;
+ u32 count, now = jiffies / HZ;
+
+ if (now != challenge_timestamp) {
+ u32 half = (sysctl_tcp_challenge_ack_limit + 1) >> 1;
+
+ challenge_timestamp = now;
+ ACCESS_ONCE(challenge_count) =
+ half + (u32)(
+ ((u64) random32() * sysctl_tcp_challenge_ack_limit)
+ >> 32);
+ }
+ count = ACCESS_ONCE(challenge_count);
+ if (count > 0) {
+ ACCESS_ONCE(challenge_count) = count - 1;
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK);
+ tcp_send_ack(sk);
+ }
+}
+
+static void tcp_store_ts_recent(struct tcp_sock *tp)
+{
+ tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval;
+ tp->rx_opt.ts_recent_stamp = get_seconds();
+}
+
+static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
+{
+ if (tp->rx_opt.saw_tstamp && !after(seq, tp->rcv_wup)) {
+ /* PAWS bug workaround wrt. ACK frames, the PAWS discard
+ * extra check below makes sure this can only happen
+ * for pure ACK frames. -DaveM
+ *
+ * Not only, also it occurs for expired timestamps.
+ */
+
+ if (tcp_paws_check(&tp->rx_opt, 0))
+ tcp_store_ts_recent(tp);
+ }
+}
+
/* This routine deals with incoming acks, but not outgoing ones. */
static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
{
/* If the ack is older than previous acks
* then we can probably ignore it.
*/
- if (before(ack, prior_snd_una))
+ if (before(ack, prior_snd_una)) {
+ /* RFC 5961 5.2 [Blind Data Injection Attack].[Mitigation] */
+ if (before(ack, prior_snd_una - tp->max_window)) {
+ tcp_send_challenge_ack(sk);
+ return -1;
+ }
goto old_ack;
+ }
/* If the ack includes data we haven't sent yet, discard
* this segment (RFC793 Section 3.9).
prior_fackets = tp->fackets_out;
prior_in_flight = tcp_packets_in_flight(tp);
+ /* ts_recent update must be made after we are sure that the packet
+ * is in window.
+ */
+ if (flag & FLAG_UPDATE_TS_RECENT)
+ tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+
if (!(flag & FLAG_SLOWPATH) && after(ack, prior_snd_una)) {
/* Window is constant, pure forward advance.
* No more checks are required.
EXPORT_SYMBOL(tcp_parse_md5sig_option);
#endif
-static inline void tcp_store_ts_recent(struct tcp_sock *tp)
-{
- tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval;
- tp->rx_opt.ts_recent_stamp = get_seconds();
-}
-
-static inline void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
-{
- if (tp->rx_opt.saw_tstamp && !after(seq, tp->rcv_wup)) {
- /* PAWS bug workaround wrt. ACK frames, the PAWS discard
- * extra check below makes sure this can only happen
- * for pure ACK frames. -DaveM
- *
- * Not only, also it occurs for expired timestamps.
- */
-
- if (tcp_paws_check(&tp->rx_opt, 0))
- tcp_store_ts_recent(tp);
- }
-}
-
/* Sorry, PAWS as specified is broken wrt. pure-ACKs -DaveM
*
* It is not fatal. If this ACK does _not_ change critical state (seqs, window)
/* Does PAWS and seqno based validation of an incoming segment, flags will
* play significant role here.
*/
-static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
- const struct tcphdr *th, int syn_inerr)
+static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
+ const struct tcphdr *th, int syn_inerr)
{
const u8 *hash_location;
struct tcp_sock *tp = tcp_sk(sk);
* an acknowledgment should be sent in reply (unless the RST
* bit is set, if so drop the segment and return)".
*/
- if (!th->rst)
+ if (!th->rst) {
+ if (th->syn)
+ goto syn_challenge;
tcp_send_dupack(sk, skb);
+ }
goto discard;
}
/* Step 2: check RST bit */
if (th->rst) {
- tcp_reset(sk);
+ /* RFC 5961 3.2 :
+ * If sequence number exactly matches RCV.NXT, then
+ * RESET the connection
+ * else
+ * Send a challenge ACK
+ */
+ if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt)
+ tcp_reset(sk);
+ else
+ tcp_send_challenge_ack(sk);
goto discard;
}
- /* ts_recent update must be made after we are sure that the packet
- * is in window.
- */
- tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
-
/* step 3: check security and precedence [ignored] */
- /* step 4: Check for a SYN in window. */
- if (th->syn && !before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
+ /* step 4: Check for a SYN
+ * RFC 5691 4.2 : Send a challenge ack
+ */
+ if (th->syn) {
+syn_challenge:
if (syn_inerr)
TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
- NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONSYN);
- tcp_reset(sk);
- return -1;
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE);
+ tcp_send_challenge_ack(sk);
+ goto discard;
}
- return 1;
+ return true;
discard:
__kfree_skb(skb);
- return 0;
+ return false;
}
/*
const struct tcphdr *th, unsigned int len)
{
struct tcp_sock *tp = tcp_sk(sk);
- int res;
/*
* Header prediction.
if (tp->copied_seq == tp->rcv_nxt &&
len - tcp_header_len <= tp->ucopy.len) {
#ifdef CONFIG_NET_DMA
- if (tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
+ if (tp->ucopy.task == current &&
+ sock_owned_by_user(sk) &&
+ tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
copied_early = 1;
eaten = 1;
}
if (tcp_checksum_complete_user(sk, skb))
goto csum_error;
+ if ((int)skb->truesize > sk->sk_forward_alloc)
+ goto step5;
+
/* Predicted packet is in window by definition.
* seq == rcv_nxt and rcv_wup <= rcv_nxt.
* Hence, check seq<=rcv_wup reduces to:
tcp_rcv_rtt_measure_ts(sk, skb);
- if ((int)skb->truesize > sk->sk_forward_alloc)
- goto step5;
-
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITS);
/* Bulk data transfer: receiver */
* Standard slow path.
*/
- res = tcp_validate_incoming(sk, skb, th, 1);
- if (res <= 0)
- return -res;
+ if (!tcp_validate_incoming(sk, skb, th, 1))
+ return 0;
step5:
- if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0)
+ if (th->ack &&
+ tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT) < 0)
goto discard;
tcp_rcv_rtt_measure_ts(sk, skb);
}
tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
+ tp->copied_seq = tp->rcv_nxt;
tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
/* RFC1323: The window in SYN & SYN/ACK segments is
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
int queued = 0;
- int res;
tp->rx_opt.saw_tstamp = 0;
goto discard;
if (th->syn) {
+ if (th->fin)
+ goto discard;
if (icsk->icsk_af_ops->conn_request(sk, skb) < 0)
return 1;
return 0;
}
- res = tcp_validate_incoming(sk, skb, th, 0);
- if (res <= 0)
- return -res;
+ if (!tcp_validate_incoming(sk, skb, th, 0))
+ return 0;
/* step 5: check the ACK field */
if (th->ack) {
- int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH) > 0;
+ int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH |
+ FLAG_UPDATE_TS_RECENT) > 0;
switch (sk->sk_state) {
case TCP_SYN_RECV:
git.openpandora.org / pandora-kernel.git / blobdiff