Current code assume that all (except last) packets are of the same size. This is definitely wrong. Replace SACK code with a new one, that does not rely on this assumption. Also this code uses less memory.
Signed-off-by: Mikhail Kshevetskiy mikhail.kshevetskiy@iopsys.eu --- net/tcp.c | 200 +++++++++++++++++++++++------------------------------- 1 file changed, 86 insertions(+), 114 deletions(-)
diff --git a/net/tcp.c b/net/tcp.c index 3e3118de450..724536cb352 100644 --- a/net/tcp.c +++ b/net/tcp.c @@ -38,21 +38,6 @@ static u32 tcp_ack_edge;
static int tcp_activity_count;
-/* - * Search for TCP_SACK and review the comments before the code section - * TCP_SACK is the number of packets at the front of the stream - */ - -enum pkt_state {PKT, NOPKT}; -struct sack_r { - struct sack_edges se; - enum pkt_state st; -}; - -static struct sack_r edge_a[TCP_SACK]; -static unsigned int sack_idx; -static unsigned int prev_len; - /* * TCP lengths are stored as a rounded up number of 32 bit words. * Add 3 to length round up, rounded, then divided into the @@ -69,6 +54,11 @@ static enum tcp_state current_tcp_state; /* Current TCP RX packet handler */ static rxhand_tcp *tcp_packet_handler;
+static inline s32 tcp_seq_cmp(u32 a, u32 b) +{ + return (s32)(a - b); +} + /** * tcp_get_tcp_state() - get current TCP state * @@ -267,6 +257,7 @@ int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len, action = TCP_FIN; current_tcp_state = TCP_FIN_WAIT_1; } else { + tcp_lost.len = TCP_OPT_LEN_2; current_tcp_state = TCP_SYN_SENT; } break; @@ -353,6 +344,20 @@ int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len, return pkt_hdr_len; }
+static void tcp_update_ack_edge(void) +{ + if (tcp_seq_cmp(tcp_ack_edge, tcp_lost.hill[0].l) >= 0) { + tcp_ack_edge = tcp_lost.hill[0].r; + + memmove(&tcp_lost.hill[0], &tcp_lost.hill[1], + (TCP_SACK_HILLS - 1) * sizeof(struct sack_edges)); + + tcp_lost.len -= TCP_OPT_LEN_8; + tcp_lost.hill[TCP_SACK_HILLS - 1].l = TCP_O_NOP; + tcp_lost.hill[TCP_SACK_HILLS - 1].r = TCP_O_NOP; + } +} + /** * tcp_hole() - Selective Acknowledgment (Essential for fast stream transfer) * @tcp_seq_num: TCP sequence start number @@ -360,106 +365,79 @@ int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len, */ void tcp_hole(u32 tcp_seq_num, u32 len) { - u32 idx_sack, sack_in; - u32 sack_end = TCP_SACK - 1; - u32 hill = 0; - enum pkt_state expect = PKT; - u32 seq = tcp_seq_num - tcp_seq_init; - u32 hol_l = tcp_ack_edge - tcp_seq_init; - u32 hol_r = 0; - - /* Place new seq number in correct place in receive array */ - if (prev_len == 0) - prev_len = len; - - idx_sack = sack_idx + ((tcp_seq_num - tcp_ack_edge) / prev_len); - if (idx_sack < TCP_SACK) { - edge_a[idx_sack].se.l = tcp_seq_num; - edge_a[idx_sack].se.r = tcp_seq_num + len; - edge_a[idx_sack].st = PKT; + int i, j, cnt, cnt_move;
- /* - * The fin (last) packet is not the same length as data - * packets, and if it's length is recorded and used for - * array index calculation, calculation breaks. - */ - if (prev_len < len) - prev_len = len; - } + cnt = (tcp_lost.len - TCP_OPT_LEN_2) / TCP_OPT_LEN_8; + for (i = 0; i < cnt; i++) { + if (tcp_seq_cmp(tcp_lost.hill[i].r, tcp_seq_num) < 0) + continue; + if (tcp_seq_cmp(tcp_lost.hill[i].l, tcp_seq_num + len) > 0) + break;
- debug_cond(DEBUG_DEV_PKT, - "TCP 1 seq %d, edg %d, len %d, sack_idx %d, sack_end %d\n", - seq, hol_l, len, sack_idx, sack_end); + if (tcp_seq_cmp(tcp_lost.hill[i].l, tcp_seq_num) > 0) + tcp_lost.hill[i].l = tcp_seq_num; + if (tcp_seq_cmp(tcp_lost.hill[i].l, tcp_seq_num) < 0) { + len += tcp_seq_num - tcp_lost.hill[i].l; + tcp_seq_num = tcp_lost.hill[i].l; + } + if (tcp_seq_cmp(tcp_lost.hill[i].r, tcp_seq_num + len) >= 0) { + tcp_update_ack_edge(); + return; + }
- /* Right edge of contiguous stream, is the left edge of first hill */ - hol_l = tcp_seq_num - tcp_seq_init; - hol_r = hol_l + len; + /* check overlapping with next hills */ + cnt_move = 0; + tcp_lost.hill[i].r = tcp_seq_num + len; + for (j = i + 1; j < cnt; j++) { + if (tcp_seq_cmp(tcp_lost.hill[j].l, tcp_lost.hill[i].r) > 0) + break;
- if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) - tcp_lost.len = TCP_OPT_LEN_2; + tcp_lost.hill[i].r = tcp_lost.hill[j].r; + cnt_move++; + }
- debug_cond(DEBUG_DEV_PKT, - "TCP 1 in %d, seq %d, pkt_l %d, pkt_r %d, sack_idx %d, sack_end %d\n", - idx_sack, seq, hol_l, hol_r, sack_idx, sack_end); - - for (sack_in = sack_idx; sack_in < sack_end && hill < TCP_SACK_HILLS; - sack_in++) { - switch (expect) { - case NOPKT: - switch (edge_a[sack_in].st) { - case NOPKT: - debug_cond(DEBUG_INT_STATE, "N"); - break; - case PKT: - debug_cond(DEBUG_INT_STATE, "n"); - if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) { - tcp_lost.hill[hill].l = - edge_a[sack_in].se.l; - tcp_lost.hill[hill].r = - edge_a[sack_in].se.r; - } - expect = PKT; - break; - } - break; - case PKT: - switch (edge_a[sack_in].st) { - case NOPKT: - debug_cond(DEBUG_INT_STATE, "p"); - if (sack_in > sack_idx && - hill < TCP_SACK_HILLS) { - hill++; - if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) - tcp_lost.len += TCP_OPT_LEN_8; - } - expect = NOPKT; - break; - case PKT: - debug_cond(DEBUG_INT_STATE, "P"); - - if (tcp_ack_edge == edge_a[sack_in].se.l) { - tcp_ack_edge = edge_a[sack_in].se.r; - edge_a[sack_in].st = NOPKT; - sack_idx++; - } else { - if (IS_ENABLED(CONFIG_PROT_TCP_SACK) && - hill < TCP_SACK_HILLS) - tcp_lost.hill[hill].r = - edge_a[sack_in].se.r; - if (IS_ENABLED(CONFIG_PROT_TCP_SACK) && - sack_in == sack_end - 1) - tcp_lost.hill[hill].r = - edge_a[sack_in].se.r; - } - break; + if (cnt_move > 0) { + if (cnt > i + cnt_move + 1) + memmove(&tcp_lost.hill[i + 1], + &tcp_lost.hill[i + cnt_move + 1], + cnt_move * sizeof(struct sack_edges)); + + cnt -= cnt_move; + tcp_lost.len = TCP_OPT_LEN_2 + cnt * TCP_OPT_LEN_8; + for (j = cnt; j < TCP_SACK_HILLS; j++) { + tcp_lost.hill[j].l = TCP_O_NOP; + tcp_lost.hill[j].r = TCP_O_NOP; } - break; } + + tcp_update_ack_edge(); + return; } - debug_cond(DEBUG_INT_STATE, "\n"); - if (!IS_ENABLED(CONFIG_PROT_TCP_SACK) || tcp_lost.len <= TCP_OPT_LEN_2) - sack_idx = 0; -} + + if (i == TCP_SACK_HILLS) { + tcp_update_ack_edge(); + return; + } + + if (cnt < TCP_SACK_HILLS) { + cnt_move = cnt - i; + cnt++; + } else { + cnt = TCP_SACK_HILLS; + cnt_move = TCP_SACK_HILLS - i; + } + + if (cnt_move > 0) + memmove(&tcp_lost.hill[i + 1], + &tcp_lost.hill[i], + cnt_move * sizeof(struct sack_edges)); + + tcp_lost.hill[i].l = tcp_seq_num; + tcp_lost.hill[i].r = tcp_seq_num + len; + tcp_lost.len = TCP_OPT_LEN_2 + cnt * TCP_OPT_LEN_8; + + tcp_update_ack_edge(); +};
/** * tcp_parse_options() - parsing TCP options @@ -509,7 +487,6 @@ static u8 tcp_state_machine(u8 tcp_flags, u32 tcp_seq_num, int payload_len) u8 tcp_push = tcp_flags & TCP_PUSH; u8 tcp_ack = tcp_flags & TCP_ACK; u8 action = TCP_DATA; - int i;
/* * tcp_flags are examined to determine TX action in a given state @@ -536,6 +513,7 @@ static u8 tcp_state_machine(u8 tcp_flags, u32 tcp_seq_num, int payload_len) action = TCP_SYN | TCP_ACK; tcp_seq_init = tcp_seq_num; tcp_ack_edge = tcp_seq_num + 1; + tcp_lost.len = TCP_OPT_LEN_2; current_tcp_state = TCP_SYN_RECEIVED; } else if (tcp_ack || tcp_fin) { action = TCP_DATA; @@ -552,13 +530,7 @@ static u8 tcp_state_machine(u8 tcp_flags, u32 tcp_seq_num, int payload_len) action |= TCP_ACK; tcp_seq_init = tcp_seq_num; tcp_ack_edge = tcp_seq_num + 1; - sack_idx = 0; - edge_a[sack_idx].se.l = tcp_ack_edge; - edge_a[sack_idx].se.r = tcp_ack_edge; - prev_len = 0; current_tcp_state = TCP_ESTABLISHED; - for (i = 0; i < TCP_SACK; i++) - edge_a[i].st = NOPKT;
if (tcp_syn && tcp_ack) action |= TCP_PUSH;