ng_l2tp: improve seq structure locking.
Cover few cases of access to seq without lock missed in 702f98951d5. There are no known bugs fixed with this change, however. With INVARIANTS embed ng_l2tp_seq_check() into lock/unlock macros. Slightly reduce number of locks/unlocks per packet keeping the lock between functions. Reviewed by: mjg, markj Differential Revision: https://reviews.freebsd.org/D31476
This commit is contained in:
Gleb Smirnoff
parent
b2954f0a8f
commit
0a76c63dd4
@ -188,10 +188,6 @@ static void ng_l2tp_seq_rack_timeout(node_p node, hook_p hook,
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static hookpriv_p ng_l2tp_find_session(priv_p privp, u_int16_t sid);
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static ng_fn_eachhook ng_l2tp_reset_session;
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#ifdef INVARIANTS
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static void ng_l2tp_seq_check(struct l2tp_seq *seq);
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#endif
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/* Parse type for struct ng_l2tp_seq_config. */
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static const struct ng_parse_struct_field
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ng_l2tp_seq_config_fields[] = NG_L2TP_SEQ_CONFIG_TYPE_INFO;
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@ -335,12 +331,22 @@ static struct ng_type ng_l2tp_typestruct = {
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};
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NETGRAPH_INIT(l2tp, &ng_l2tp_typestruct);
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/* Sequence number state sanity checking */
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/* Sequence number state locking & sanity checking */
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#ifdef INVARIANTS
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#define L2TP_SEQ_CHECK(seq) ng_l2tp_seq_check(seq)
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static void ng_l2tp_seq_check(struct l2tp_seq *seq);
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#define SEQ_LOCK(seq) do { \
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mtx_lock(&(seq)->mtx); \
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ng_l2tp_seq_check(seq); \
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} while (0)
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#define SEQ_UNLOCK(seq) do { \
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ng_l2tp_seq_check(seq); \
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mtx_unlock(&(seq)->mtx); \
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} while (0)
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#else
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#define L2TP_SEQ_CHECK(x) do { } while (0)
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#define SEQ_LOCK(seq) mtx_lock(&(seq)->mtx)
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#define SEQ_UNLOCK(seq) mtx_unlock(&(seq)->mtx)
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#endif
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#define SEQ_LOCK_ASSERT(seq) mtx_assert(&(seq)->mtx, MA_OWNED)
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/* Whether to use m_copypacket() or m_dup() */
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#define L2TP_COPY_MBUF m_copypacket
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@ -650,11 +656,10 @@ ng_l2tp_shutdown(node_p node)
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const priv_p priv = NG_NODE_PRIVATE(node);
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struct l2tp_seq *const seq = &priv->seq;
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/* Sanity check */
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L2TP_SEQ_CHECK(seq);
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/* Reset sequence number state */
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SEQ_LOCK(seq);
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ng_l2tp_seq_reset(priv);
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SEQ_UNLOCK(seq);
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/* Free private data if neither timer is running */
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ng_uncallout(&seq->rack_timer, node);
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@ -757,9 +762,6 @@ ng_l2tp_rcvdata_lower(hook_p h, item_p item)
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int error;
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int len, plen;
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/* Sanity check */
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L2TP_SEQ_CHECK(&priv->seq);
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/* If not configured, reject */
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if (!priv->conf.enabled) {
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NG_FREE_ITEM(item);
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@ -899,18 +901,20 @@ ng_l2tp_rcvdata_lower(hook_p h, item_p item)
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if ((hdr & L2TP_HDR_CTRL) != 0) {
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struct l2tp_seq *const seq = &priv->seq;
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SEQ_LOCK(seq);
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/* Handle receive ack sequence number Nr */
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ng_l2tp_seq_recv_nr(priv, nr);
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/* Discard ZLB packets */
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if (m->m_pkthdr.len == 0) {
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SEQ_UNLOCK(seq);
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priv->stats.recvZLBs++;
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NG_FREE_ITEM(item);
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NG_FREE_M(m);
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ERROUT(0);
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}
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mtx_lock(&seq->mtx);
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/*
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* If not what we expect or we are busy, drop packet and
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* send an immediate ZLB ack.
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@ -920,23 +924,16 @@ ng_l2tp_rcvdata_lower(hook_p h, item_p item)
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priv->stats.recvDuplicates++;
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else
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priv->stats.recvOutOfOrder++;
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mtx_unlock(&seq->mtx);
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ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
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NG_FREE_ITEM(item);
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NG_FREE_M(m);
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ERROUT(0);
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}
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/*
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* Until we deliver this packet we can't receive next one as
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* we have no information for sending ack.
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*/
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seq->inproc = 1;
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mtx_unlock(&seq->mtx);
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/* Prepend session ID to packet. */
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M_PREPEND(m, 2, M_NOWAIT);
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if (m == NULL) {
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seq->inproc = 0;
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SEQ_UNLOCK(seq);
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priv->stats.memoryFailures++;
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NG_FREE_ITEM(item);
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ERROUT(ENOBUFS);
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@ -944,10 +941,17 @@ ng_l2tp_rcvdata_lower(hook_p h, item_p item)
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mtod(m, u_int8_t *)[0] = sid >> 8;
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mtod(m, u_int8_t *)[1] = sid & 0xff;
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/*
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* Until we deliver this packet we can't receive next one as
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* we have no information for sending ack.
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*/
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seq->inproc = 1;
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SEQ_UNLOCK(seq);
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/* Deliver packet to upper layers */
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NG_FWD_NEW_DATA(error, item, priv->ctrl, m);
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mtx_lock(&seq->mtx);
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SEQ_LOCK(seq);
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/* Ready to process next packet. */
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seq->inproc = 0;
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@ -962,7 +966,7 @@ ng_l2tp_rcvdata_lower(hook_p h, item_p item)
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NULL, 0);
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}
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}
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mtx_unlock(&seq->mtx);
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SEQ_UNLOCK(seq);
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ERROUT(error);
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}
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@ -997,8 +1001,6 @@ ng_l2tp_rcvdata_lower(hook_p h, item_p item)
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/* Deliver data */
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NG_FWD_NEW_DATA(error, item, hook, m);
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done:
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/* Done */
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L2TP_SEQ_CHECK(&priv->seq);
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return (error);
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}
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@ -1016,9 +1018,6 @@ ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
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int i;
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u_int16_t ns;
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/* Sanity check */
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L2TP_SEQ_CHECK(&priv->seq);
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/* If not configured, reject */
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if (!priv->conf.enabled) {
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NG_FREE_ITEM(item);
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@ -1043,12 +1042,12 @@ ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
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ERROUT(EOVERFLOW);
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}
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mtx_lock(&seq->mtx);
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SEQ_LOCK(seq);
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/* Find next empty slot in transmit queue */
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for (i = 0; i < L2TP_MAX_XWIN && seq->xwin[i] != NULL; i++);
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if (i == L2TP_MAX_XWIN) {
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mtx_unlock(&seq->mtx);
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SEQ_UNLOCK(seq);
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priv->stats.xmitDrops++;
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m_freem(m);
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ERROUT(ENOBUFS);
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@ -1057,7 +1056,7 @@ ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
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/* If peer's receive window is already full, nothing else to do */
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if (i >= seq->cwnd) {
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mtx_unlock(&seq->mtx);
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SEQ_UNLOCK(seq);
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ERROUT(0);
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}
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@ -1068,10 +1067,9 @@ ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
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ns = seq->ns++;
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mtx_unlock(&seq->mtx);
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/* Copy packet */
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if ((m = L2TP_COPY_MBUF(m, M_NOWAIT)) == NULL) {
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SEQ_UNLOCK(seq);
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priv->stats.memoryFailures++;
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ERROUT(ENOBUFS);
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}
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@ -1079,8 +1077,6 @@ ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
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/* Send packet and increment xmit sequence number */
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error = ng_l2tp_xmit_ctrl(priv, m, ns);
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done:
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/* Done */
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L2TP_SEQ_CHECK(&priv->seq);
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return (error);
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}
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@ -1098,9 +1094,6 @@ ng_l2tp_rcvdata(hook_p hook, item_p item)
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int error;
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int i = 2;
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/* Sanity check */
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L2TP_SEQ_CHECK(&priv->seq);
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/* If not configured, reject */
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if (!priv->conf.enabled) {
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NG_FREE_ITEM(item);
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@ -1161,8 +1154,6 @@ ng_l2tp_rcvdata(hook_p hook, item_p item)
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/* Send packet */
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NG_FWD_NEW_DATA(error, item, priv->lower, m);
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done:
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/* Done */
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L2TP_SEQ_CHECK(&priv->seq);
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return (error);
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}
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@ -1204,7 +1195,6 @@ ng_l2tp_seq_init(priv_p priv)
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ng_callout_init(&seq->rack_timer);
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ng_callout_init(&seq->xack_timer);
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mtx_init(&seq->mtx, "ng_l2tp", NULL, MTX_DEF);
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L2TP_SEQ_CHECK(seq);
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}
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/*
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@ -1240,10 +1230,13 @@ ng_l2tp_seq_adjust(priv_p priv, const struct ng_l2tp_config *conf)
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{
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struct l2tp_seq *const seq = &priv->seq;
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u_int16_t new_wmax;
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int error = 0;
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SEQ_LOCK(seq);
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/* If disabling node, reset state sequence number */
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if (!conf->enabled) {
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ng_l2tp_seq_reset(priv);
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SEQ_UNLOCK(seq);
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return (0);
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}
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@ -1252,13 +1245,14 @@ ng_l2tp_seq_adjust(priv_p priv, const struct ng_l2tp_config *conf)
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if (new_wmax > L2TP_MAX_XWIN)
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new_wmax = L2TP_MAX_XWIN;
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if (new_wmax == 0)
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return (EINVAL);
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ERROUT(EINVAL);
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if (new_wmax < seq->wmax)
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return (EBUSY);
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ERROUT(EBUSY);
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seq->wmax = new_wmax;
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/* Done */
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return (0);
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done:
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SEQ_UNLOCK(seq);
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return (error);
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}
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/*
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@ -1271,8 +1265,7 @@ ng_l2tp_seq_reset(priv_p priv)
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hook_p hook;
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int i;
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/* Sanity check */
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L2TP_SEQ_CHECK(seq);
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SEQ_LOCK_ASSERT(seq);
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/* Stop timers */
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ng_uncallout(&seq->rack_timer, priv->node);
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@ -1299,9 +1292,6 @@ ng_l2tp_seq_reset(priv_p priv)
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seq->acks = 0;
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seq->rexmits = 0;
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bzero(seq->xwin, sizeof(seq->xwin));
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/* Done */
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L2TP_SEQ_CHECK(seq);
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}
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/*
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@ -1316,15 +1306,12 @@ ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
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int i, j;
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uint16_t ns;
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mtx_lock(&seq->mtx);
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SEQ_LOCK_ASSERT(seq);
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/* Verify peer's ACK is in range */
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if ((nack = L2TP_SEQ_DIFF(nr, seq->rack)) <= 0) {
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mtx_unlock(&seq->mtx);
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if ((nack = L2TP_SEQ_DIFF(nr, seq->rack)) <= 0)
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return; /* duplicate ack */
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}
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if (L2TP_SEQ_DIFF(nr, seq->ns) > 0) {
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mtx_unlock(&seq->mtx);
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priv->stats.recvBadAcks++; /* ack for packet not sent */
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return;
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}
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@ -1375,10 +1362,8 @@ ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
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ng_uncallout(&seq->rack_timer, priv->node);
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/* If transmit queue is empty, we're done for now */
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if (seq->xwin[0] == NULL) {
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mtx_unlock(&seq->mtx);
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if (seq->xwin[0] == NULL)
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return;
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}
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/* Start restransmit timer again */
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ng_callout(&seq->rack_timer, priv->node, NULL,
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@ -1396,8 +1381,6 @@ ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
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seq->ns++;
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}
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mtx_unlock(&seq->mtx);
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/*
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* Send prepared.
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* If there is a memory error, pretend packet was sent, as it
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@ -1407,8 +1390,10 @@ ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
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struct mbuf *m;
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if ((m = L2TP_COPY_MBUF(xwin[i], M_NOWAIT)) == NULL)
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priv->stats.memoryFailures++;
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else
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else {
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ng_l2tp_xmit_ctrl(priv, m, ns);
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SEQ_LOCK(seq);
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}
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ns++;
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}
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}
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@ -1428,17 +1413,13 @@ ng_l2tp_seq_xack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
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(!callout_active(&seq->xack_timer)))
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return;
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/* Sanity check */
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L2TP_SEQ_CHECK(seq);
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SEQ_LOCK(seq);
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/* Send a ZLB */
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ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
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/* callout_deactivate() is not needed here
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as ng_uncallout() was called by ng_l2tp_xmit_ctrl() */
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/* Sanity check */
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L2TP_SEQ_CHECK(seq);
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}
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/*
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@ -1453,14 +1434,12 @@ ng_l2tp_seq_rack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
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struct mbuf *m;
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u_int delay;
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/* Sanity check */
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L2TP_SEQ_CHECK(seq);
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SEQ_LOCK(seq);
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mtx_lock(&seq->mtx);
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/* Make sure callout is still active before doing anything */
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if (callout_pending(&seq->rack_timer) ||
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!callout_active(&seq->rack_timer)) {
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mtx_unlock(&seq->mtx);
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SEQ_UNLOCK(seq);
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return;
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}
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@ -1485,41 +1464,39 @@ ng_l2tp_seq_rack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
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/* Retransmit oldest unack'd packet */
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m = L2TP_COPY_MBUF(seq->xwin[0], M_NOWAIT);
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mtx_unlock(&seq->mtx);
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if (m == NULL)
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if (m == NULL) {
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SEQ_UNLOCK(seq);
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priv->stats.memoryFailures++;
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else
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} else
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ng_l2tp_xmit_ctrl(priv, m, seq->ns++);
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/* callout_deactivate() is not needed here
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as ng_callout() is getting called each time */
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/* Sanity check */
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L2TP_SEQ_CHECK(seq);
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}
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/*
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* Transmit a control stream packet, payload optional.
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* The transmit sequence number is not incremented.
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* Requires seq lock, returns unlocked.
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*/
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static int
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ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns)
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{
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struct l2tp_seq *const seq = &priv->seq;
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uint8_t *p;
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u_int16_t session_id = 0;
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uint16_t nr, session_id = 0;
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int error;
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mtx_lock(&seq->mtx);
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SEQ_LOCK_ASSERT(seq);
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/* Stop ack timer: we're sending an ack with this packet.
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Doing this before to keep state predictable after error. */
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if (callout_active(&seq->xack_timer))
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ng_uncallout(&seq->xack_timer, priv->node);
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seq->xack = seq->nr;
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nr = seq->xack = seq->nr;
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mtx_unlock(&seq->mtx);
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SEQ_UNLOCK(seq);
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/* If no mbuf passed, send an empty packet (ZLB) */
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if (m == NULL) {
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@ -1570,8 +1547,8 @@ ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns)
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p[7] = session_id & 0xff;
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p[8] = ns >> 8;
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p[9] = ns & 0xff;
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p[10] = seq->nr >> 8;
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p[11] = seq->nr & 0xff;
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p[10] = nr >> 8;
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p[11] = nr & 0xff;
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/* Update sequence number info and stats */
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priv->stats.xmitPackets++;
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@ -1594,7 +1571,7 @@ ng_l2tp_seq_check(struct l2tp_seq *seq)
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#define CHECK(p) KASSERT((p), ("%s: not: %s", __func__, #p))
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mtx_lock(&seq->mtx);
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SEQ_LOCK_ASSERT(seq);
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self_unack = L2TP_SEQ_DIFF(seq->nr, seq->xack);
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peer_unack = L2TP_SEQ_DIFF(seq->ns, seq->rack);
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@ -1617,8 +1594,6 @@ ng_l2tp_seq_check(struct l2tp_seq *seq)
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for ( ; i < seq->cwnd; i++) /* verify peer's recv window full */
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CHECK(seq->xwin[i] == NULL);
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mtx_unlock(&seq->mtx);
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#undef CHECK
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}
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#endif /* INVARIANTS */
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