1 files changed, 64 insertions, 114 deletions

diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
index 01e4d39fa232..85ad70cfba5b 100644
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -1,7 +1,8 @@
 /*
  *  net/dccp/ackvec.c
  *
- *  An implementation of the DCCP protocol
+ *  An implementation of Ack Vectors for the DCCP protocol
+ *  Copyright (c) 2007 University of Aberdeen, Scotland, UK
  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
  *
  *      This program is free software; you can redistribute it and/or modify it
@@ -23,24 +24,32 @@
 static struct kmem_cache *dccp_ackvec_slab;
 static struct kmem_cache *dccp_ackvec_record_slab;
 
-static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
+struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
 {
-        struct dccp_ackvec_record *avr =
-                        kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
+        struct dccp_ackvec *av = kmem_cache_zalloc(dccp_ackvec_slab, priority);
+
+        if (av != NULL) {
+                av->av_buf_head = DCCPAV_MAX_ACKVEC_LEN - 1;
+                INIT_LIST_HEAD(&av->av_records);
+        }
+        return av;
+}
 
-        if (avr != NULL)
-                INIT_LIST_HEAD(&avr->avr_node);
+static void dccp_ackvec_purge_records(struct dccp_ackvec *av)
+{
+        struct dccp_ackvec_record *cur, *next;
 
-        return avr;
+        list_for_each_entry_safe(cur, next, &av->av_records, avr_node)
+                kmem_cache_free(dccp_ackvec_record_slab, cur);
+        INIT_LIST_HEAD(&av->av_records);
 }
 
-static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
+void dccp_ackvec_free(struct dccp_ackvec *av)
 {
-        if (unlikely(avr == NULL))
-                return;
-        /* Check if deleting a linked record */
-        WARN_ON(!list_empty(&avr->avr_node));
-        kmem_cache_free(dccp_ackvec_record_slab, avr);
+        if (likely(av != NULL)) {
+                dccp_ackvec_purge_records(av);
+                kmem_cache_free(dccp_ackvec_slab, av);
+        }
 }
 
 static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
@@ -68,24 +77,16 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
         struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
         /* Figure out how many options do we need to represent the ackvec */
         const u8 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_SINGLE_OPT_MAXLEN);
-        u16 len = av->av_vec_len + 2 * nr_opts, i;
-        u32 elapsed_time;
+        u16 len = av->av_vec_len + 2 * nr_opts;
+        u8 i, nonce = 0;
         const unsigned char *tail, *from;
         unsigned char *to;
         struct dccp_ackvec_record *avr;
-        suseconds_t delta;
 
         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
                 return -1;
 
-        delta = ktime_us_delta(ktime_get_real(), av->av_time);
-        elapsed_time = delta / 10;
-
-        if (elapsed_time != 0 &&
-            dccp_insert_option_elapsed_time(sk, skb, elapsed_time))
-                return -1;
-
-        avr = dccp_ackvec_record_new();
+        avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
         if (avr == NULL)
                 return -1;
 
@@ -94,7 +95,7 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
         to   = skb_push(skb, len);
         len  = av->av_vec_len;
         from = av->av_buf + av->av_buf_head;
-        tail = av->av_buf + DCCP_MAX_ACKVEC_LEN;
+        tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
 
         for (i = 0; i < nr_opts; ++i) {
                 int copylen = len;
@@ -102,7 +103,13 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
                 if (len > DCCP_SINGLE_OPT_MAXLEN)
                         copylen = DCCP_SINGLE_OPT_MAXLEN;
 
-                *to++ = DCCPO_ACK_VECTOR_0;
+                /*
+                 * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via
+                 * its type; ack_nonce is the sum of all individual buf_nonce's.
+                 */
+                nonce ^= av->av_buf_nonce[i];
+
+                *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i];
                 *to++ = copylen + 2;
 
                 /* Check if buf_head wraps */
@@ -123,75 +130,24 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
         }
 
         /*
-         *      From RFC 4340, A.2:
-         *
-         *      For each acknowledgement it sends, the HC-Receiver will add an
-         *      acknowledgement record.  ack_seqno will equal the HC-Receiver
-         *      sequence number it used for the ack packet; ack_ptr will equal
-         *      buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
-         *      equal buf_nonce.
+         * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.
          */
-        avr->avr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
-        avr->avr_ack_ptr   = av->av_buf_head;
-        avr->avr_ack_ackno = av->av_buf_ackno;
-        avr->avr_ack_nonce = av->av_buf_nonce;
-        avr->avr_sent_len  = av->av_vec_len;
+        avr->avr_ack_seqno  = DCCP_SKB_CB(skb)->dccpd_seq;
+        avr->avr_ack_ptr    = av->av_buf_head;
+        avr->avr_ack_ackno  = av->av_buf_ackno;
+        avr->avr_ack_nonce  = nonce;
+        avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head);
 
         dccp_ackvec_insert_avr(av, avr);
 
         dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
                       "ack_ackno=%llu\n",
-                      dccp_role(sk), avr->avr_sent_len,
+                      dccp_role(sk), avr->avr_ack_runlen,
                       (unsigned long long)avr->avr_ack_seqno,
                       (unsigned long long)avr->avr_ack_ackno);
         return 0;
 }
 
-struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
-{
-        struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority);
-
-        if (av != NULL) {
-                av->av_buf_head  = DCCP_MAX_ACKVEC_LEN - 1;
-                av->av_buf_ackno = UINT48_MAX + 1;
-                av->av_buf_nonce = 0;
-                av->av_time      = ktime_set(0, 0);
-                av->av_vec_len   = 0;
-                INIT_LIST_HEAD(&av->av_records);
-        }
-
-        return av;
-}
-
-void dccp_ackvec_free(struct dccp_ackvec *av)
-{
-        if (unlikely(av == NULL))
-                return;
-
-        if (!list_empty(&av->av_records)) {
-                struct dccp_ackvec_record *avr, *next;
-
-                list_for_each_entry_safe(avr, next, &av->av_records, avr_node) {
-                        list_del_init(&avr->avr_node);
-                        dccp_ackvec_record_delete(avr);
-                }
-        }
-
-        kmem_cache_free(dccp_ackvec_slab, av);
-}
-
-static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
-                                   const u32 index)
-{
-        return av->av_buf[index] & DCCP_ACKVEC_STATE_MASK;
-}
-
-static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
-                                 const u32 index)
-{
-        return av->av_buf[index] & DCCP_ACKVEC_LEN_MASK;
-}
-
 /*
  * If several packets are missing, the HC-Receiver may prefer to enter multiple
  * bytes with run length 0, rather than a single byte with a larger run length;
@@ -204,7 +160,7 @@ static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
         unsigned int gap;
         long new_head;
 
-        if (av->av_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
+        if (av->av_vec_len + packets > DCCPAV_MAX_ACKVEC_LEN)
                 return -ENOBUFS;
 
         gap      = packets - 1;
@@ -212,18 +168,18 @@ static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
 
         if (new_head < 0) {
                 if (gap > 0) {
-                        memset(av->av_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
+                        memset(av->av_buf, DCCPAV_NOT_RECEIVED,
                                gap + new_head + 1);
                         gap = -new_head;
                 }
-                new_head += DCCP_MAX_ACKVEC_LEN;
+                new_head += DCCPAV_MAX_ACKVEC_LEN;
         }
 
         av->av_buf_head = new_head;
 
         if (gap > 0)
                 memset(av->av_buf + av->av_buf_head + 1,
-                       DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
+                       DCCPAV_NOT_RECEIVED, gap);
 
         av->av_buf[av->av_buf_head] = state;
         av->av_vec_len += packets;
@@ -236,6 +192,8 @@ static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
 int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
                     const u64 ackno, const u8 state)
 {
+        u8 *cur_head = av->av_buf + av->av_buf_head,
+           *buf_end  = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
         /*
          * Check at the right places if the buffer is full, if it is, tell the
          * caller to start dropping packets till the HC-Sender acks our ACK
@@ -260,7 +218,7 @@ int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
 
         /* See if this is the first ackno being inserted */
         if (av->av_vec_len == 0) {
-                av->av_buf[av->av_buf_head] = state;
+                *cur_head = state;
                 av->av_vec_len = 1;
         } else if (after48(ackno, av->av_buf_ackno)) {
                 const u64 delta = dccp_delta_seqno(av->av_buf_ackno, ackno);
@@ -269,10 +227,9 @@ int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
                  * Look if the state of this packet is the same as the
                  * previous ackno and if so if we can bump the head len.
                  */
-                if (delta == 1 &&
-                    dccp_ackvec_state(av, av->av_buf_head) == state &&
-                    dccp_ackvec_len(av, av->av_buf_head) < DCCP_ACKVEC_LEN_MASK)
-                        av->av_buf[av->av_buf_head]++;
+                if (delta == 1 && dccp_ackvec_state(cur_head) == state &&
+                    dccp_ackvec_runlen(cur_head) < DCCPAV_MAX_RUNLEN)
+                        *cur_head += 1;
                 else if (dccp_ackvec_set_buf_head_state(av, delta, state))
                         return -ENOBUFS;
         } else {
@@ -285,21 +242,17 @@ int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
                  *      could reduce the complexity of this scan.)
                  */
                 u64 delta = dccp_delta_seqno(ackno, av->av_buf_ackno);
-                u32 index = av->av_buf_head;
 
                 while (1) {
-                        const u8 len = dccp_ackvec_len(av, index);
-                        const u8 av_state = dccp_ackvec_state(av, index);
+                        const u8 len = dccp_ackvec_runlen(cur_head);
                         /*
                          * valid packets not yet in av_buf have a reserved
                          * entry, with a len equal to 0.
                          */
-                        if (av_state == DCCP_ACKVEC_STATE_NOT_RECEIVED &&
-                            len == 0 && delta == 0) { /* Found our
-                                                         reserved seat! */
+                        if (*cur_head == DCCPAV_NOT_RECEIVED && delta == 0) {
                                 dccp_pr_debug("Found %llu reserved seat!\n",
                                               (unsigned long long)ackno);
-                                av->av_buf[index] = state;
+                                *cur_head = state;
                                 goto out;
                         }
                         /* len == 0 means one packet */
@@ -307,13 +260,12 @@ int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
                                 goto out_duplicate;
 
                         delta -= len + 1;
-                        if (++index == DCCP_MAX_ACKVEC_LEN)
-                                index = 0;
+                        if (++cur_head == buf_end)
+                                cur_head = av->av_buf;
                 }
         }
 
         av->av_buf_ackno = ackno;
-        av->av_time = ktime_get_real();
 out:
         return 0;
 
@@ -333,13 +285,13 @@ static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
         if (av->av_buf_head <= avr->avr_ack_ptr)
                 av->av_vec_len = avr->avr_ack_ptr - av->av_buf_head;
         else
-                av->av_vec_len = DCCP_MAX_ACKVEC_LEN - 1 -
+                av->av_vec_len = DCCPAV_MAX_ACKVEC_LEN - 1 -
                                  av->av_buf_head + avr->avr_ack_ptr;
 
         /* free records */
         list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) {
-                list_del_init(&avr->avr_node);
-                dccp_ackvec_record_delete(avr);
+                list_del(&avr->avr_node);
+                kmem_cache_free(dccp_ackvec_record_slab, avr);
         }
 }
 
@@ -357,7 +309,7 @@ void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
                 if (ackno == avr->avr_ack_seqno) {
                         dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, "
                                       "ack_ackno=%llu, ACKED!\n",
-                                      dccp_role(sk), 1,
+                                      dccp_role(sk), avr->avr_ack_runlen,
                                       (unsigned long long)avr->avr_ack_seqno,
                                       (unsigned long long)avr->avr_ack_ackno);
                         dccp_ackvec_throw_record(av, avr);
@@ -387,7 +339,7 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
          */
         avr = list_entry(av->av_records.next, struct dccp_ackvec_record, avr_node);
         while (i--) {
-                const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
+                const u8 rl = dccp_ackvec_runlen(vector);
                 u64 ackno_end_rl;
 
                 dccp_set_seqno(&ackno_end_rl, *ackno - rl);
@@ -404,8 +356,7 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
                 break;
 found:
                 if (between48(avr->avr_ack_seqno, ackno_end_rl, *ackno)) {
-                        const u8 state = *vector & DCCP_ACKVEC_STATE_MASK;
-                        if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
+                        if (dccp_ackvec_state(vector) != DCCPAV_NOT_RECEIVED) {
                                 dccp_pr_debug("%s ACK vector 0, len=%d, "
                                               "ack_seqno=%llu, ack_ackno=%llu, "
                                               "ACKED!\n",
@@ -448,10 +399,9 @@ int __init dccp_ackvec_init(void)
         if (dccp_ackvec_slab == NULL)
                 goto out_err;
 
-        dccp_ackvec_record_slab =
-                        kmem_cache_create("dccp_ackvec_record",
-                                          sizeof(struct dccp_ackvec_record),
-                                          0, SLAB_HWCACHE_ALIGN, NULL);
+        dccp_ackvec_record_slab = kmem_cache_create("dccp_ackvec_record",
+                                             sizeof(struct dccp_ackvec_record),
+                                             0, SLAB_HWCACHE_ALIGN, NULL);
         if (dccp_ackvec_record_slab == NULL)
                 goto out_destroy_slab;