dccp ccid-2: Separate internals of Ack Vectors from option-parsing code

This patch
 * separates Ack Vector housekeeping code from option-insertion code;
 * shifts option-specific code from ackvec.c into options.c;
 * introduces a dedicated routine to take care of the Ack Vector records;
 * simplifies the dccp_ackvec_insert_avr() routine: the BUG_ON was redundant,
   since the list is automatically arranged in descending order of ack_seqno.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
index 17bf10f9605793bdf50528f735c86548d493b7d9..af976fca407ab38d38999c08e09a31c485f17aed 100644 (file)
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -52,99 +52,35 @@ void dccp_ackvec_free(struct dccp_ackvec *av)
        }
 }
 
-static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
-                                  struct dccp_ackvec_record *avr)
-{
-       /*
-        * AVRs are sorted by seqno. Since we are sending them in order, we
-        * just add the AVR at the head of the list.
-        * -sorbo.
-        */
-       if (!list_empty(&av->av_records)) {
-               const struct dccp_ackvec_record *head =
-                                       list_entry(av->av_records.next,
-                                                  struct dccp_ackvec_record,
-                                                  avr_node);
-               BUG_ON(before48(avr->avr_ack_seqno, head->avr_ack_seqno));
-       }
-
-       list_add(&avr->avr_node, &av->av_records);
-}
-
-int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
+/**
+ * dccp_ackvec_update_records  -  Record information about sent Ack Vectors
+ * @av:                Ack Vector records to update
+ * @seqno:     Sequence number of the packet carrying the Ack Vector just sent
+ * @nonce_sum: The sum of all buffer nonces contained in the Ack Vector
+ */
+int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum)
 {
-       struct dccp_sock *dp = dccp_sk(sk);
-       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;
-       u8 i, nonce = 0;
-       const unsigned char *tail, *from;
-       unsigned char *to;
        struct dccp_ackvec_record *avr;
 
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
-               return -1;
-
        avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
        if (avr == NULL)
-               return -1;
-
-       DCCP_SKB_CB(skb)->dccpd_opt_len += len;
-
-       to   = skb_push(skb, len);
-       len  = av->av_vec_len;
-       from = av->av_buf + av->av_buf_head;
-       tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
-
-       for (i = 0; i < nr_opts; ++i) {
-               int copylen = len;
-
-               if (len > DCCP_SINGLE_OPT_MAXLEN)
-                       copylen = DCCP_SINGLE_OPT_MAXLEN;
-
-               /*
-                * 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 */
-               if (from + copylen > tail) {
-                       const u16 tailsize = tail - from;
-
-                       memcpy(to, from, tailsize);
-                       to      += tailsize;
-                       len     -= tailsize;
-                       copylen -= tailsize;
-                       from    = av->av_buf;
-               }
-
-               memcpy(to, from, copylen);
-               from += copylen;
-               to   += copylen;
-               len  -= copylen;
-       }
+               return -ENOBUFS;
 
-       /*
-        * 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_seqno  = seqno;
        avr->avr_ack_ptr    = av->av_buf_head;
        avr->avr_ack_ackno  = av->av_buf_ackno;
-       avr->avr_ack_nonce  = nonce;
+       avr->avr_ack_nonce  = nonce_sum;
        avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head);
+       /*
+        * Since GSS is incremented for each packet, the list is automatically
+        * arranged in descending order of @ack_seqno.
+        */
+       list_add(&avr->avr_node, &av->av_records);
 
-       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_ack_runlen,
+       dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n",
                      (unsigned long long)avr->avr_ack_seqno,
-                     (unsigned long long)avr->avr_ack_ackno);
+                     (unsigned long long)avr->avr_ack_ackno,
+                     avr->avr_ack_runlen);
        return 0;
 }
 

diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h
index ebcbbc726cffa00e583d4618f92b6d47da1ffcbd..3e894a0173a76817ec52214fecfe7af9c8accf98 100644 (file)
--- a/net/dccp/ackvec.h
+++ b/net/dccp/ackvec.h
@@ -111,7 +111,7 @@ extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
                             u64 *ackno, const u8 opt,
                             const u8 *value, const u8 len);
 
-extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
+extern int  dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
 
 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
 {

diff --git a/net/dccp/options.c b/net/dccp/options.c
index 799c6f4547cdac18c1f355aef9c5a3e0417764ca..f4ff0a308269582e901911b082c6d4404bcf360e 100644 (file)
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -425,6 +425,66 @@ static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
        return 0;
 }
 
+static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
+{
+       struct dccp_sock *dp = dccp_sk(sk);
+       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;
+       u8 i, nonce = 0;
+       const unsigned char *tail, *from;
+       unsigned char *to;
+
+       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+               return -1;
+
+       DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+       to   = skb_push(skb, len);
+       len  = av->av_vec_len;
+       from = av->av_buf + av->av_buf_head;
+       tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
+
+       for (i = 0; i < nr_opts; ++i) {
+               int copylen = len;
+
+               if (len > DCCP_SINGLE_OPT_MAXLEN)
+                       copylen = DCCP_SINGLE_OPT_MAXLEN;
+
+               /*
+                * 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 */
+               if (from + copylen > tail) {
+                       const u16 tailsize = tail - from;
+
+                       memcpy(to, from, tailsize);
+                       to      += tailsize;
+                       len     -= tailsize;
+                       copylen -= tailsize;
+                       from    = av->av_buf;
+               }
+
+               memcpy(to, from, copylen);
+               from += copylen;
+               to   += copylen;
+               len  -= copylen;
+       }
+       /*
+        * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.
+        */
+       if (dccp_ackvec_update_records(av, DCCP_SKB_CB(skb)->dccpd_seq, nonce))
+               return -ENOBUFS;
+       return 0;
+}
+
 /**
  * dccp_insert_option_mandatory  -  Mandatory option (5.8.2)
  * Note that since we are using skb_push, this function needs to be called