dccp: Add packet type information to CCID-specific option parsing

This patch ...
 1. adds packet type information to ccid_hc_{rx,tx}_parse_options(). This is
    necessary, since table 3 in RFC 4340, 5.8 leaves it to the CCIDs to state
    which options may (not) appear on what packet type.

 2. adds such a check for CCID-3's {Loss Event, Receive} Rate as specified in
    RFC 4340 8.3 ("Receive Rate options MUST NOT be sent on DCCP-Data packets")
    and 8.5 ("Loss Event Rate options MUST NOT be sent on DCCP-Data packets").

 3. removes an unused argument `idx' from ccid_hc_{rx,tx}_parse_options(). This
    is also no longer necessary, since the CCID-specific option-parsing routines
    are passed every single parameter of the type-length-value option encoding.

Also added documentation and made argument naming scheme consistent.

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

diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index 20ba066..bce517c 100644 (file)
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -60,18 +60,14 @@ struct ccid_operations {
        void            (*ccid_hc_tx_exit)(struct sock *sk);
        void            (*ccid_hc_rx_packet_recv)(struct sock *sk,
                                                  struct sk_buff *skb);
-       int             (*ccid_hc_rx_parse_options)(struct sock *sk,
-                                                   unsigned char option,
-                                                   unsigned char len, u16 idx,
-                                                   unsigned char* value);
+       int             (*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt,
+                                                   u8 opt, u8 *val, u8 len);
        int             (*ccid_hc_rx_insert_options)(struct sock *sk,
                                                     struct sk_buff *skb);
        void            (*ccid_hc_tx_packet_recv)(struct sock *sk,
                                                  struct sk_buff *skb);
-       int             (*ccid_hc_tx_parse_options)(struct sock *sk,
-                                                   unsigned char option,
-                                                   unsigned char len, u16 idx,
-                                                   unsigned char* value);
+       int             (*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt,
+                                                   u8 opt, u8 *val, u8 len);
        int             (*ccid_hc_tx_send_packet)(struct sock *sk,
                                                  struct sk_buff *skb);
        void            (*ccid_hc_tx_packet_sent)(struct sock *sk,
@@ -163,27 +159,31 @@ static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
                ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
 }
 
+/**
+ * ccid_hc_tx_parse_options  -  Parse CCID-specific options sent by the receiver
+ * @pkt: type of packet that @opt appears on (RFC 4340, 5.1)
+ * @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3)
+ * @val: value of @opt
+ * @len: length of @val in bytes
+ */
 static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
-                                          unsigned char option,
-                                          unsigned char len, u16 idx,
-                                          unsigned char* value)
+                                          u8 pkt, u8 opt, u8 *val, u8 len)
 {
-       int rc = 0;
-       if (ccid->ccid_ops->ccid_hc_tx_parse_options != NULL)
-               rc = ccid->ccid_ops->ccid_hc_tx_parse_options(sk, option, len, idx,
-                                                   value);
-       return rc;
+       if (ccid->ccid_ops->ccid_hc_tx_parse_options == NULL)
+               return 0;
+       return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len);
 }
 
+/**
+ * ccid_hc_rx_parse_options  -  Parse CCID-specific options sent by the sender
+ * Arguments are analogous to ccid_hc_tx_parse_options()
+ */
 static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
-                                          unsigned char option,
-                                          unsigned char len, u16 idx,
-                                          unsigned char* value)
+                                          u8 pkt, u8 opt, u8 *val, u8 len)
 {
-       int rc = 0;
-       if (ccid->ccid_ops->ccid_hc_rx_parse_options != NULL)
-               rc = ccid->ccid_ops->ccid_hc_rx_parse_options(sk, option, len, idx, value);
-       return rc;
+       if (ccid->ccid_ops->ccid_hc_rx_parse_options == NULL)
+               return 0;
+       return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len);
 }
 
 static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 12b601f..4c422fb 100644 (file)
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -483,9 +483,8 @@ done_computing_x:
                           jiffies + usecs_to_jiffies(t_nfb));
 }
 
-static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
-                                    unsigned char len, u16 idx,
-                                    unsigned char *value)
+static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+                                    u8 option, u8 *optval, u8 optlen)
 {
        struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
        struct ccid3_options_received *opt_recv = &hctx->options_received;
@@ -494,12 +493,15 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
        switch (option) {
        case TFRC_OPT_RECEIVE_RATE:
        case TFRC_OPT_LOSS_EVENT_RATE:
-               if (unlikely(len != 4)) {
+               /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
+               if (packet_type == DCCP_PKT_DATA)
+                       break;
+               if (unlikely(optlen != 4)) {
                        DCCP_WARN("%s(%p), invalid len %d for %u\n",
-                                 dccp_role(sk), sk, len, option);
+                                 dccp_role(sk), sk, optlen, option);
                        return -EINVAL;
                }
-               opt_val = ntohl(get_unaligned((__be32 *)value));
+               opt_val = ntohl(get_unaligned((__be32 *)optval));
 
                if (option == TFRC_OPT_RECEIVE_RATE) {
                        opt_recv->ccid3or_receive_rate = opt_val;

diff --git a/net/dccp/options.c b/net/dccp/options.c
index fd51cc7..b102774 100644 (file)
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -226,23 +226,15 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
                        dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
                                      dccp_role(sk), elapsed_time);
                        break;
-               case 128 ... 191: {
-                       const u16 idx = value - options;
-
+               case 128 ... 191:
                        if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
-                                                    opt, len, idx,
-                                                    value) != 0)
+                                                    pkt_type, opt, value, len))
                                goto out_invalid_option;
-               }
                        break;
-               case 192 ... 255: {
-                       const u16 idx = value - options;
-
+               case 192 ... 255:
                        if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
-                                                    opt, len, idx,
-                                                    value) != 0)
+                                                    pkt_type, opt, value, len))
                                goto out_invalid_option;
-               }
                        break;
                default:
                        DCCP_CRIT("DCCP(%p): option %d(len=%d) not "