dccp ccid-2: Separate option parsing from CCID processing
This patch replaces an almost identical replication of code: large parts
of dccp_parse_options() re-appeared as ccid2_ackvector() in ccid2.c.
Apart from the duplication, this caused two more problems:
1. CCIDs should not need to be concerned with parsing header options;
2. one can not assume that Ack Vectors appear as a contiguous area within an
skb, it is legal to insert other options and/or padding in between. The
current code would throw an error and stop reading in such a case.
Since Ack Vectors provide CCID-specific information, they are now processed
by the CCID directly, separating this functionality from the main DCCP code.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index cb1b4a0..e96d5e8 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -246,68 +246,6 @@
#endif
}
-/* XXX Lame code duplication!
- * returns -1 if none was found.
- * else returns the next offset to use in the function call.
- */
-static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
- unsigned char **vec, unsigned char *veclen)
-{
- const struct dccp_hdr *dh = dccp_hdr(skb);
- unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
- unsigned char *opt_ptr;
- const unsigned char *opt_end = (unsigned char *)dh +
- (dh->dccph_doff * 4);
- unsigned char opt, len;
- unsigned char *value;
-
- BUG_ON(offset < 0);
- options += offset;
- opt_ptr = options;
- if (opt_ptr >= opt_end)
- return -1;
-
- while (opt_ptr != opt_end) {
- opt = *opt_ptr++;
- len = 0;
- value = NULL;
-
- /* Check if this isn't a single byte option */
- if (opt > DCCPO_MAX_RESERVED) {
- if (opt_ptr == opt_end)
- goto out_invalid_option;
-
- len = *opt_ptr++;
- if (len < 3)
- goto out_invalid_option;
- /*
- * Remove the type and len fields, leaving
- * just the value size
- */
- len -= 2;
- value = opt_ptr;
- opt_ptr += len;
-
- if (opt_ptr > opt_end)
- goto out_invalid_option;
- }
-
- switch (opt) {
- case DCCPO_ACK_VECTOR_0:
- case DCCPO_ACK_VECTOR_1:
- *vec = value;
- *veclen = len;
- return offset + (opt_ptr - options);
- }
- }
-
- return -1;
-
-out_invalid_option:
- DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
- return -1;
-}
-
/**
* ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm
* This code is almost identical with TCP's tcp_rtt_estimator(), since
@@ -432,16 +370,28 @@
ccid2_change_l_ack_ratio(sk, hc->tx_cwnd);
}
+static int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+ u8 option, u8 *optval, u8 optlen)
+{
+ struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+
+ switch (option) {
+ case DCCPO_ACK_VECTOR_0:
+ case DCCPO_ACK_VECTOR_1:
+ return dccp_ackvec_parsed_add(&hc->tx_av_chunks, optval, optlen,
+ option - DCCPO_ACK_VECTOR_0);
+ }
+ return 0;
+}
+
static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
+ struct dccp_ackvec_parsed *avp;
u64 ackno, seqno;
struct ccid2_seq *seqp;
- unsigned char *vector;
- unsigned char veclen;
- int offset = 0;
int done = 0;
unsigned int maxincr = 0;
@@ -475,17 +425,12 @@
}
/* check forward path congestion */
- /* still didn't send out new data packets */
- if (hc->tx_seqh == hc->tx_seqt)
+ if (dccp_packet_without_ack(skb))
return;
- switch (DCCP_SKB_CB(skb)->dccpd_type) {
- case DCCP_PKT_ACK:
- case DCCP_PKT_DATAACK:
- break;
- default:
- return;
- }
+ /* still didn't send out new data packets */
+ if (hc->tx_seqh == hc->tx_seqt)
+ goto done;
ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
if (after48(ackno, hc->tx_high_ack))
@@ -509,15 +454,16 @@
maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
/* go through all ack vectors */
- while ((offset = ccid2_ackvector(sk, skb, offset,
- &vector, &veclen)) != -1) {
+ list_for_each_entry(avp, &hc->tx_av_chunks, node) {
/* go through this ack vector */
- while (veclen--) {
- u64 ackno_end_rl = SUB48(ackno, dccp_ackvec_runlen(vector));
+ for (; avp->len--; avp->vec++) {
+ u64 ackno_end_rl = SUB48(ackno,
+ dccp_ackvec_runlen(avp->vec));
- ccid2_pr_debug("ackvec start:%llu end:%llu\n",
+ ccid2_pr_debug("ackvec %llu |%u,%u|\n",
(unsigned long long)ackno,
- (unsigned long long)ackno_end_rl);
+ dccp_ackvec_state(avp->vec) >> 6,
+ dccp_ackvec_runlen(avp->vec));
/* if the seqno we are analyzing is larger than the
* current ackno, then move towards the tail of our
* seqnos.
@@ -536,7 +482,7 @@
* run length
*/
while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
- const u8 state = dccp_ackvec_state(vector);
+ const u8 state = dccp_ackvec_state(avp->vec);
/* new packet received or marked */
if (state != DCCPAV_NOT_RECEIVED &&
@@ -563,7 +509,6 @@
break;
ackno = SUB48(ackno_end_rl, 1);
- vector++;
}
if (done)
break;
@@ -631,10 +576,11 @@
sk_stop_timer(sk, &hc->tx_rtotimer);
else
sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
-
+done:
/* check if incoming Acks allow pending packets to be sent */
if (sender_was_blocked && !ccid2_cwnd_network_limited(hc))
tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
+ dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks);
}
static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -663,6 +609,7 @@
hc->tx_last_cong = ccid2_time_stamp;
setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire,
(unsigned long)sk);
+ INIT_LIST_HEAD(&hc->tx_av_chunks);
return 0;
}
@@ -696,16 +643,17 @@
}
struct ccid_operations ccid2_ops = {
- .ccid_id = DCCPC_CCID2,
- .ccid_name = "TCP-like",
- .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
- .ccid_hc_tx_init = ccid2_hc_tx_init,
- .ccid_hc_tx_exit = ccid2_hc_tx_exit,
- .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
- .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
- .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
- .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
- .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
+ .ccid_id = DCCPC_CCID2,
+ .ccid_name = "TCP-like",
+ .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
+ .ccid_hc_tx_init = ccid2_hc_tx_init,
+ .ccid_hc_tx_exit = ccid2_hc_tx_exit,
+ .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
+ .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
+ .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options,
+ .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
+ .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
+ .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
};
#ifdef CONFIG_IP_DCCP_CCID2_DEBUG