net/tcp: fix selective acknowledge
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> Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Mikhail Kshevetskiy
committed by
Tom Rini
Tom Rini
parent
77da29b868
commit
40d3d6557d
206
net/tcp.c
206
net/tcp.c
@@ -38,21 +38,6 @@ static u32 tcp_ack_edge;
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static int tcp_activity_count;
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/*
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* Search for TCP_SACK and review the comments before the code section
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* TCP_SACK is the number of packets at the front of the stream
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*/
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enum pkt_state {PKT, NOPKT};
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struct sack_r {
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struct sack_edges se;
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enum pkt_state st;
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};
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static struct sack_r edge_a[TCP_SACK];
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static unsigned int sack_idx;
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static unsigned int prev_len;
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/*
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* TCP lengths are stored as a rounded up number of 32 bit words.
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* Add 3 to length round up, rounded, then divided into the
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@@ -69,6 +54,11 @@ static enum tcp_state current_tcp_state;
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/* Current TCP RX packet handler */
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static rxhand_tcp *tcp_packet_handler;
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static inline s32 tcp_seq_cmp(u32 a, u32 b)
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{
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return (s32)(a - b);
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}
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/**
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* tcp_get_tcp_state() - get current TCP state
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*
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@@ -267,6 +257,7 @@ int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len,
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action = TCP_FIN;
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current_tcp_state = TCP_FIN_WAIT_1;
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} else {
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tcp_lost.len = TCP_OPT_LEN_2;
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current_tcp_state = TCP_SYN_SENT;
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}
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break;
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@@ -353,6 +344,20 @@ int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len,
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return pkt_hdr_len;
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}
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static void tcp_update_ack_edge(void)
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{
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if (tcp_seq_cmp(tcp_ack_edge, tcp_lost.hill[0].l) >= 0) {
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tcp_ack_edge = tcp_lost.hill[0].r;
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memmove(&tcp_lost.hill[0], &tcp_lost.hill[1],
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(TCP_SACK_HILLS - 1) * sizeof(struct sack_edges));
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tcp_lost.len -= TCP_OPT_LEN_8;
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tcp_lost.hill[TCP_SACK_HILLS - 1].l = TCP_O_NOP;
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tcp_lost.hill[TCP_SACK_HILLS - 1].r = TCP_O_NOP;
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}
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}
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/**
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* tcp_hole() - Selective Acknowledgment (Essential for fast stream transfer)
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* @tcp_seq_num: TCP sequence start number
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@@ -360,106 +365,79 @@ int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len,
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*/
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void tcp_hole(u32 tcp_seq_num, u32 len)
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{
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u32 idx_sack, sack_in;
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u32 sack_end = TCP_SACK - 1;
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u32 hill = 0;
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enum pkt_state expect = PKT;
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u32 seq = tcp_seq_num - tcp_seq_init;
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u32 hol_l = tcp_ack_edge - tcp_seq_init;
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u32 hol_r = 0;
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int i, j, cnt, cnt_move;
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/* Place new seq number in correct place in receive array */
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if (prev_len == 0)
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prev_len = len;
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idx_sack = sack_idx + ((tcp_seq_num - tcp_ack_edge) / prev_len);
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if (idx_sack < TCP_SACK) {
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edge_a[idx_sack].se.l = tcp_seq_num;
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edge_a[idx_sack].se.r = tcp_seq_num + len;
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edge_a[idx_sack].st = PKT;
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/*
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* The fin (last) packet is not the same length as data
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* packets, and if it's length is recorded and used for
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* array index calculation, calculation breaks.
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*/
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if (prev_len < len)
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prev_len = len;
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}
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debug_cond(DEBUG_DEV_PKT,
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"TCP 1 seq %d, edg %d, len %d, sack_idx %d, sack_end %d\n",
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seq, hol_l, len, sack_idx, sack_end);
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/* Right edge of contiguous stream, is the left edge of first hill */
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hol_l = tcp_seq_num - tcp_seq_init;
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hol_r = hol_l + len;
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if (IS_ENABLED(CONFIG_PROT_TCP_SACK))
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tcp_lost.len = TCP_OPT_LEN_2;
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debug_cond(DEBUG_DEV_PKT,
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"TCP 1 in %d, seq %d, pkt_l %d, pkt_r %d, sack_idx %d, sack_end %d\n",
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idx_sack, seq, hol_l, hol_r, sack_idx, sack_end);
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for (sack_in = sack_idx; sack_in < sack_end && hill < TCP_SACK_HILLS;
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sack_in++) {
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switch (expect) {
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case NOPKT:
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switch (edge_a[sack_in].st) {
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case NOPKT:
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debug_cond(DEBUG_INT_STATE, "N");
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break;
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case PKT:
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debug_cond(DEBUG_INT_STATE, "n");
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if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) {
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tcp_lost.hill[hill].l =
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edge_a[sack_in].se.l;
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tcp_lost.hill[hill].r =
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edge_a[sack_in].se.r;
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}
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expect = PKT;
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break;
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}
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cnt = (tcp_lost.len - TCP_OPT_LEN_2) / TCP_OPT_LEN_8;
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for (i = 0; i < cnt; i++) {
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if (tcp_seq_cmp(tcp_lost.hill[i].r, tcp_seq_num) < 0)
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continue;
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if (tcp_seq_cmp(tcp_lost.hill[i].l, tcp_seq_num + len) > 0)
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break;
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case PKT:
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switch (edge_a[sack_in].st) {
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case NOPKT:
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debug_cond(DEBUG_INT_STATE, "p");
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if (sack_in > sack_idx &&
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hill < TCP_SACK_HILLS) {
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hill++;
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if (IS_ENABLED(CONFIG_PROT_TCP_SACK))
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tcp_lost.len += TCP_OPT_LEN_8;
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}
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expect = NOPKT;
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break;
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case PKT:
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debug_cond(DEBUG_INT_STATE, "P");
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if (tcp_ack_edge == edge_a[sack_in].se.l) {
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tcp_ack_edge = edge_a[sack_in].se.r;
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edge_a[sack_in].st = NOPKT;
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sack_idx++;
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} else {
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if (IS_ENABLED(CONFIG_PROT_TCP_SACK) &&
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hill < TCP_SACK_HILLS)
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tcp_lost.hill[hill].r =
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edge_a[sack_in].se.r;
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if (IS_ENABLED(CONFIG_PROT_TCP_SACK) &&
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sack_in == sack_end - 1)
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tcp_lost.hill[hill].r =
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edge_a[sack_in].se.r;
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}
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break;
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}
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break;
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if (tcp_seq_cmp(tcp_lost.hill[i].l, tcp_seq_num) > 0)
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tcp_lost.hill[i].l = tcp_seq_num;
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if (tcp_seq_cmp(tcp_lost.hill[i].l, tcp_seq_num) < 0) {
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len += tcp_seq_num - tcp_lost.hill[i].l;
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tcp_seq_num = tcp_lost.hill[i].l;
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}
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if (tcp_seq_cmp(tcp_lost.hill[i].r, tcp_seq_num + len) >= 0) {
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tcp_update_ack_edge();
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return;
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}
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/* check overlapping with next hills */
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cnt_move = 0;
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tcp_lost.hill[i].r = tcp_seq_num + len;
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for (j = i + 1; j < cnt; j++) {
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if (tcp_seq_cmp(tcp_lost.hill[j].l, tcp_lost.hill[i].r) > 0)
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break;
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tcp_lost.hill[i].r = tcp_lost.hill[j].r;
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cnt_move++;
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}
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if (cnt_move > 0) {
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if (cnt > i + cnt_move + 1)
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memmove(&tcp_lost.hill[i + 1],
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&tcp_lost.hill[i + cnt_move + 1],
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cnt_move * sizeof(struct sack_edges));
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cnt -= cnt_move;
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tcp_lost.len = TCP_OPT_LEN_2 + cnt * TCP_OPT_LEN_8;
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for (j = cnt; j < TCP_SACK_HILLS; j++) {
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tcp_lost.hill[j].l = TCP_O_NOP;
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tcp_lost.hill[j].r = TCP_O_NOP;
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}
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}
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tcp_update_ack_edge();
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return;
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}
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debug_cond(DEBUG_INT_STATE, "\n");
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if (!IS_ENABLED(CONFIG_PROT_TCP_SACK) || tcp_lost.len <= TCP_OPT_LEN_2)
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sack_idx = 0;
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}
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if (i == TCP_SACK_HILLS) {
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tcp_update_ack_edge();
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return;
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}
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if (cnt < TCP_SACK_HILLS) {
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cnt_move = cnt - i;
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cnt++;
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} else {
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cnt = TCP_SACK_HILLS;
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cnt_move = TCP_SACK_HILLS - i;
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}
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if (cnt_move > 0)
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memmove(&tcp_lost.hill[i + 1],
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&tcp_lost.hill[i],
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cnt_move * sizeof(struct sack_edges));
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tcp_lost.hill[i].l = tcp_seq_num;
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tcp_lost.hill[i].r = tcp_seq_num + len;
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tcp_lost.len = TCP_OPT_LEN_2 + cnt * TCP_OPT_LEN_8;
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tcp_update_ack_edge();
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};
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/**
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* tcp_parse_options() - parsing TCP options
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@@ -509,7 +487,6 @@ static u8 tcp_state_machine(u8 tcp_flags, u32 tcp_seq_num, int payload_len)
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u8 tcp_push = tcp_flags & TCP_PUSH;
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u8 tcp_ack = tcp_flags & TCP_ACK;
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u8 action = TCP_DATA;
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int i;
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/*
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* tcp_flags are examined to determine TX action in a given state
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@@ -536,6 +513,7 @@ static u8 tcp_state_machine(u8 tcp_flags, u32 tcp_seq_num, int payload_len)
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action = TCP_SYN | TCP_ACK;
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tcp_seq_init = tcp_seq_num;
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tcp_ack_edge = tcp_seq_num + 1;
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tcp_lost.len = TCP_OPT_LEN_2;
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current_tcp_state = TCP_SYN_RECEIVED;
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} else if (tcp_ack || tcp_fin) {
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action = TCP_DATA;
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@@ -552,13 +530,7 @@ static u8 tcp_state_machine(u8 tcp_flags, u32 tcp_seq_num, int payload_len)
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action |= TCP_ACK;
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tcp_seq_init = tcp_seq_num;
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tcp_ack_edge = tcp_seq_num + 1;
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sack_idx = 0;
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edge_a[sack_idx].se.l = tcp_ack_edge;
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edge_a[sack_idx].se.r = tcp_ack_edge;
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prev_len = 0;
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current_tcp_state = TCP_ESTABLISHED;
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for (i = 0; i < TCP_SACK; i++)
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edge_a[i].st = NOPKT;
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if (tcp_syn && tcp_ack)
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action |= TCP_PUSH;
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