dccp ccid-3: Simplify and consolidate tx_parse_options

This simplifies and consolidates the TX option-parsing code:

 1. The Loss Intervals option is not currently used, so dead code related to
    this option is removed. I am aware of no plans to support the option, but
    if someone wants to implement it (e.g. for inter-op tests), it is better
    to start afresh than having to also update currently unused code.

 2. The Loss Event and Receive Rate options have a lot of code in common (both
    are 32 bit, both have same length etc.), so this is consolidated.

 3. The test against GSR is not necessary, because
    - on first loading CCID3, ccid_new() zeroes out all fields in the socket;
    - ccid3_hc_tx_packet_recv() treats 0 and ~0U equivalently, due to

	pinv = opt_recv->ccid3or_loss_event_rate;
	if (pinv == ~0U || pinv == 0)
		hctx->p = 0;

    - as a result, the sequence number field is removed from opt_recv.

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

2 files changed, 14 insertions, 46 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index b2ddd205d438..ce8059130070 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -485,60 +485,31 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
                                      unsigned char len, u16 idx,
                                      unsigned char *value)
 {
-        int rc = 0;
-        const struct dccp_sock *dp = dccp_sk(sk);
         struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
         struct ccid3_options_received *opt_recv = &hc->tx_options_received;
         __be32 opt_val;
 
-        if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
-                opt_recv->ccid3or_seqno              = dp->dccps_gsr;
-                opt_recv->ccid3or_loss_event_rate    = ~0;
-                opt_recv->ccid3or_loss_intervals_idx = 0;
-                opt_recv->ccid3or_loss_intervals_len = 0;
-                opt_recv->ccid3or_receive_rate       = 0;
-        }
-
         switch (option) {
+        case TFRC_OPT_RECEIVE_RATE:
         case TFRC_OPT_LOSS_EVENT_RATE:
                 if (unlikely(len != 4)) {
-                        DCCP_WARN("%s(%p), invalid len %d "
-                                  "for TFRC_OPT_LOSS_EVENT_RATE\n",
-                                  dccp_role(sk), sk, len);
-                        rc = -EINVAL;
-                } else {
-                        opt_val = get_unaligned((__be32 *)value);
-                        opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
-                        ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
-                                       dccp_role(sk), sk,
-                                       opt_recv->ccid3or_loss_event_rate);
+                        DCCP_WARN("%s(%p), invalid len %d for %u\n",
+                                  dccp_role(sk), sk, len, option);
+                        return -EINVAL;
                 }
-                break;
-        case TFRC_OPT_LOSS_INTERVALS:
-                opt_recv->ccid3or_loss_intervals_idx = idx;
-                opt_recv->ccid3or_loss_intervals_len = len;
-                ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
-                               dccp_role(sk), sk,
-                               opt_recv->ccid3or_loss_intervals_idx,
-                               opt_recv->ccid3or_loss_intervals_len);
-                break;
-        case TFRC_OPT_RECEIVE_RATE:
-                if (unlikely(len != 4)) {
-                        DCCP_WARN("%s(%p), invalid len %d "
-                                  "for TFRC_OPT_RECEIVE_RATE\n",
-                                  dccp_role(sk), sk, len);
-                        rc = -EINVAL;
-                } else {
-                        opt_val = get_unaligned((__be32 *)value);
-                        opt_recv->ccid3or_receive_rate = ntohl(opt_val);
+                opt_val = ntohl(get_unaligned((__be32 *)value));
+
+                if (option == TFRC_OPT_RECEIVE_RATE) {
+                        opt_recv->ccid3or_receive_rate = opt_val;
                         ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
-                                       dccp_role(sk), sk,
-                                       opt_recv->ccid3or_receive_rate);
+                                       dccp_role(sk), sk, opt_val);
+                } else {
+                        opt_recv->ccid3or_loss_event_rate = opt_val;
+                        ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
+                                       dccp_role(sk), sk, opt_val);
                 }
-                break;
         }
-
-        return rc;
+        return 0;
 }
 
 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 4a00174a97dd..9eb90b863abd 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -68,9 +68,6 @@ enum ccid3_options {
 };
 
 struct ccid3_options_received {
-        u64 ccid3or_seqno:48,
-            ccid3or_loss_intervals_idx:16;
-        u16 ccid3or_loss_intervals_len;
         u32 ccid3or_loss_event_rate;
         u32 ccid3or_receive_rate;
 };