dccp: remove unused function argument
[linux-2.6.git] / net / dccp / options.c
index 382c589..4973bad 100644 (file)
@@ -4,77 +4,72 @@
  *  An implementation of the DCCP protocol
  *  Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
- *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
+ *  Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
  */
-#include <linux/config.h>
 #include <linux/dccp.h>
 #include <linux/module.h>
 #include <linux/types.h>
+#include <asm/unaligned.h>
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 
+#include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
+#include "feat.h"
 
-static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
-                                            struct sock *sk,
-                                            const u64 ackno,
-                                            const unsigned char len,
-                                            const unsigned char *vector);
-
-/* stores the default values for new connection. may be changed with sysctl */
-static const struct dccp_options dccpo_default_values = {
-       .dccpo_sequence_window    = DCCPF_INITIAL_SEQUENCE_WINDOW,
-       .dccpo_ccid               = DCCPF_INITIAL_CCID,
-       .dccpo_send_ack_vector    = DCCPF_INITIAL_SEND_ACK_VECTOR,
-       .dccpo_send_ndp_count     = DCCPF_INITIAL_SEND_NDP_COUNT,
-};
-
-void dccp_options_init(struct dccp_options *dccpo)
+u64 dccp_decode_value_var(const u8 *bf, const u8 len)
 {
-       memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
-}
-
-static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
-{
-       u32 value = 0;
+       u64 value = 0;
 
+       if (len >= DCCP_OPTVAL_MAXLEN)
+               value += ((u64)*bf++) << 40;
+       if (len > 4)
+               value += ((u64)*bf++) << 32;
        if (len > 3)
-               value += *bf++ << 24;
+               value += ((u64)*bf++) << 24;
        if (len > 2)
-               value += *bf++ << 16;
+               value += ((u64)*bf++) << 16;
        if (len > 1)
-               value += *bf++ << 8;
+               value += ((u64)*bf++) << 8;
        if (len > 0)
                value += *bf;
 
        return value;
 }
 
-int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
+/**
+ * dccp_parse_options  -  Parse DCCP options present in @skb
+ * @sk: client|server|listening dccp socket (when @dreq != NULL)
+ * @dreq: request socket to use during connection setup, or NULL
+ */
+int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
+                      struct sk_buff *skb)
 {
        struct dccp_sock *dp = dccp_sk(sk);
-#ifdef CONFIG_IP_DCCP_DEBUG
-       const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                       "CLIENT rx opt: " : "server rx opt: ";
-#endif
        const struct dccp_hdr *dh = dccp_hdr(skb);
        const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
+       u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
        unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
        unsigned char *opt_ptr = options;
        const unsigned char *opt_end = (unsigned char *)dh +
                                        (dh->dccph_doff * 4);
        struct dccp_options_received *opt_recv = &dp->dccps_options_received;
        unsigned char opt, len;
-       unsigned char *value;
+       unsigned char *uninitialized_var(value);
+       u32 elapsed_time;
+       __be32 opt_val;
+       int rc;
+       int mandatory = 0;
 
        memset(opt_recv, 0, sizeof(*opt_recv));
 
+       opt = len = 0;
        while (opt_ptr != opt_end) {
                opt   = *opt_ptr++;
                len   = 0;
@@ -83,11 +78,11 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                /* Check if this isn't a single byte option */
                if (opt > DCCPO_MAX_RESERVED) {
                        if (opt_ptr == opt_end)
-                               goto out_invalid_option;
+                               goto out_nonsensical_length;
 
                        len = *opt_ptr++;
-                       if (len < 3)
-                               goto out_invalid_option;
+                       if (len < 2)
+                               goto out_nonsensical_length;
                        /*
                         * Remove the type and len fields, leaving
                         * just the value size
@@ -97,52 +92,82 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                        opt_ptr += len;
 
                        if (opt_ptr > opt_end)
-                               goto out_invalid_option;
+                               goto out_nonsensical_length;
                }
 
+               /*
+                * CCID-Specific Options (from RFC 4340, sec. 10.3):
+                *
+                * Option numbers 128 through 191 are for options sent from the
+                * HC-Sender to the HC-Receiver; option numbers 192 through 255
+                * are for options sent from the HC-Receiver to the HC-Sender.
+                *
+                * CCID-specific options are ignored during connection setup, as
+                * negotiation may still be in progress (see RFC 4340, 10.3).
+                * The same applies to Ack Vectors, as these depend on the CCID.
+                *
+                */
+               if (dreq != NULL && (opt >= 128 ||
+                   opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
+                       goto ignore_option;
+
                switch (opt) {
                case DCCPO_PADDING:
                        break;
+               case DCCPO_MANDATORY:
+                       if (mandatory)
+                               goto out_invalid_option;
+                       if (pkt_type != DCCP_PKT_DATA)
+                               mandatory = 1;
+                       break;
                case DCCPO_NDP_COUNT:
-                       if (len > 3)
+                       if (len > 6)
                                goto out_invalid_option;
 
                        opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
-                       dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
-                                     opt_recv->dccpor_ndp);
+                       dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
+                                     (unsigned long long)opt_recv->dccpor_ndp);
+                       break;
+               case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
+                       if (pkt_type == DCCP_PKT_DATA)      /* RFC 4340, 6 */
+                               break;
+                       rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
+                                                   *value, value + 1, len - 1);
+                       if (rc)
+                               goto out_featneg_failed;
                        break;
                case DCCPO_ACK_VECTOR_0:
-                       if (len > DCCP_MAX_ACK_VECTOR_LEN)
+               case DCCPO_ACK_VECTOR_1:
+                       if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
+                               break;
+                       if (dp->dccps_hc_rx_ackvec != NULL &&
+                           dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
                                goto out_invalid_option;
-
-                       if (pkt_type == DCCP_PKT_DATA)
-                               continue;
-
-                       opt_recv->dccpor_ack_vector_len = len;
-                       opt_recv->dccpor_ack_vector_idx = value - options;
-
-                       dccp_pr_debug("%sACK vector 0, len=%d, ack_ackno=%llu\n",
-                                     debug_prefix, len,
-                                     (unsigned long long)
-                                     DCCP_SKB_CB(skb)->dccpd_ack_seq);
-                       dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq,
-                                            value, len);
-                       dccp_ackpkts_check_rcv_ackvector(dp->dccps_hc_rx_ackpkts,
-                                                        sk,
-                                                DCCP_SKB_CB(skb)->dccpd_ack_seq,
-                                                        len, value);
                        break;
                case DCCPO_TIMESTAMP:
                        if (len != 4)
                                goto out_invalid_option;
+                       /*
+                        * RFC 4340 13.1: "The precise time corresponding to
+                        * Timestamp Value zero is not specified". We use
+                        * zero to indicate absence of a meaningful timestamp.
+                        */
+                       opt_val = get_unaligned((__be32 *)value);
+                       if (unlikely(opt_val == 0)) {
+                               DCCP_WARN("Timestamp with zero value\n");
+                               break;
+                       }
 
-                       opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
-
-                       dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
-                       do_gettimeofday(&dp->dccps_timestamp_time);
-
-                       dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
-                                     debug_prefix, opt_recv->dccpor_timestamp,
+                       if (dreq != NULL) {
+                               dreq->dreq_timestamp_echo = ntohl(opt_val);
+                               dreq->dreq_timestamp_time = dccp_timestamp();
+                       } else {
+                               opt_recv->dccpor_timestamp =
+                                       dp->dccps_timestamp_echo = ntohl(opt_val);
+                               dp->dccps_timestamp_time = dccp_timestamp();
+                       }
+                       dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
+                                     dccp_role(sk), ntohl(opt_val),
                                      (unsigned long long)
                                      DCCP_SKB_CB(skb)->dccpd_ack_seq);
                        break;
@@ -150,54 +175,57 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                        if (len != 4 && len != 6 && len != 8)
                                goto out_invalid_option;
 
-                       opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
+                       opt_val = get_unaligned((__be32 *)value);
+                       opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
 
-                       dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
-                                     debug_prefix,
+                       dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
+                                     "ackno=%llu", dccp_role(sk),
                                      opt_recv->dccpor_timestamp_echo,
                                      len + 2,
                                      (unsigned long long)
                                      DCCP_SKB_CB(skb)->dccpd_ack_seq);
 
-                       if (len > 4) {
-                               if (len == 6)
-                                       opt_recv->dccpor_elapsed_time =
-                                                ntohs(*(u16 *)(value + 4));
-                               else
-                                       opt_recv->dccpor_elapsed_time =
-                                                ntohl(*(u32 *)(value + 4));
-
-                               dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n",
-                                     debug_prefix,
-                                     opt_recv->dccpor_elapsed_time);
+                       value += 4;
+
+                       if (len == 4) {         /* no elapsed time included */
+                               dccp_pr_debug_cat("\n");
+                               break;
+                       }
+
+                       if (len == 6) {         /* 2-byte elapsed time */
+                               __be16 opt_val2 = get_unaligned((__be16 *)value);
+                               elapsed_time = ntohs(opt_val2);
+                       } else {                /* 4-byte elapsed time */
+                               opt_val = get_unaligned((__be32 *)value);
+                               elapsed_time = ntohl(opt_val);
                        }
+
+                       dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
+
+                       /* Give precedence to the biggest ELAPSED_TIME */
+                       if (elapsed_time > opt_recv->dccpor_elapsed_time)
+                               opt_recv->dccpor_elapsed_time = elapsed_time;
                        break;
                case DCCPO_ELAPSED_TIME:
-                       if (len != 2 && len != 4)
+                       if (dccp_packet_without_ack(skb))   /* RFC 4340, 13.2 */
+                               break;
+
+                       if (len == 2) {
+                               __be16 opt_val2 = get_unaligned((__be16 *)value);
+                               elapsed_time = ntohs(opt_val2);
+                       } else if (len == 4) {
+                               opt_val = get_unaligned((__be32 *)value);
+                               elapsed_time = ntohl(opt_val);
+                       } else {
                                goto out_invalid_option;
+                       }
 
-                       if (pkt_type == DCCP_PKT_DATA)
-                               continue;
-
-                       if (len == 2)
-                               opt_recv->dccpor_elapsed_time =
-                                                       ntohs(*(u16 *)value);
-                       else
-                               opt_recv->dccpor_elapsed_time =
-                                                       ntohl(*(u32 *)value);
+                       if (elapsed_time > opt_recv->dccpor_elapsed_time)
+                               opt_recv->dccpor_elapsed_time = elapsed_time;
 
-                       dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
-                                     opt_recv->dccpor_elapsed_time);
+                       dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
+                                     dccp_role(sk), elapsed_time);
                        break;
-                       /*
-                        * From draft-ietf-dccp-spec-11.txt:
-                        *
-                        *      Option numbers 128 through 191 are for
-                        *      options sent from the HC-Sender to the
-                        *      HC-Receiver; option numbers 192 through 255
-                        *      are for options sent from the HC-Receiver to
-                        *      the HC-Sender.
-                        */
                case 128 ... 191: {
                        const u16 idx = value - options;
 
@@ -217,25 +245,43 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                }
                        break;
                default:
-                       pr_info("DCCP(%p): option %d(len=%d) not "
-                               "implemented, ignoring\n",
-                               sk, opt, len);
+                       DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
+                                 "implemented, ignoring", sk, opt, len);
                        break;
-               }
+               }
+ignore_option:
+               if (opt != DCCPO_MANDATORY)
+                       mandatory = 0;
        }
 
+       /* mandatory was the last byte in option list -> reset connection */
+       if (mandatory)
+               goto out_invalid_option;
+
+out_nonsensical_length:
+       /* RFC 4340, 5.8: ignore option and all remaining option space */
        return 0;
 
 out_invalid_option:
        DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
-       DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
-       pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
+       rc = DCCP_RESET_CODE_OPTION_ERROR;
+out_featneg_failed:
+       DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
+       DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
+       DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
+       DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
+       DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
        return -1;
 }
 
-static void dccp_encode_value_var(const u32 value, unsigned char *to,
-                                 const unsigned int len)
+EXPORT_SYMBOL_GPL(dccp_parse_options);
+
+void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
 {
+       if (len >= DCCP_OPTVAL_MAXLEN)
+               *to++ = (value & 0xFF0000000000ull) >> 40;
+       if (len > 4)
+               *to++ = (value & 0xFF00000000ull) >> 32;
        if (len > 3)
                *to++ = (value & 0xFF000000) >> 24;
        if (len > 2)
@@ -246,22 +292,20 @@ static void dccp_encode_value_var(const u32 value, unsigned char *to,
                *to++ = (value & 0xFF);
 }
 
-static inline int dccp_ndp_len(const int ndp)
+static inline u8 dccp_ndp_len(const u64 ndp)
 {
-       return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
+       if (likely(ndp <= 0xFF))
+               return 1;
+       return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
 }
 
-void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
-                       const unsigned char option,
-                       const void *value, const unsigned char len)
+int dccp_insert_option(struct sk_buff *skb, const unsigned char option,
+                      const void *value, const unsigned char len)
 {
        unsigned char *to;
 
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
-               LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
-                              "%d option!\n", option);
-               return;
-       }
+       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
+               return -1;
 
        DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
 
@@ -270,14 +314,15 @@ void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
        *to++ = len + 2;
 
        memcpy(to, value, len);
+       return 0;
 }
 
 EXPORT_SYMBOL_GPL(dccp_insert_option);
 
-static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
+static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
 {
        struct dccp_sock *dp = dccp_sk(sk);
-       int ndp = dp->dccps_ndp_count;
+       u64 ndp = dp->dccps_ndp_count;
 
        if (dccp_non_data_packet(skb))
                ++dp->dccps_ndp_count;
@@ -290,7 +335,7 @@ static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
                const int len = ndp_len + 2;
 
                if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
-                       return;
+                       return -1;
 
                DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 
@@ -299,6 +344,8 @@ static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
                *ptr++ = len;
                dccp_encode_value_var(ndp, ptr, ndp_len);
        }
+
+       return 0;
 }
 
 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
@@ -306,27 +353,17 @@ static inline int dccp_elapsed_time_len(const u32 elapsed_time)
        return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
 }
 
-void dccp_insert_option_elapsed_time(struct sock *sk,
-                                    struct sk_buff *skb,
-                                    u32 elapsed_time)
+int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time)
 {
-#ifdef CONFIG_IP_DCCP_DEBUG
-       struct dccp_sock *dp = dccp_sk(sk);
-       const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                       "CLIENT TX opt: " : "server TX opt: ";
-#endif
        const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
        const int len = 2 + elapsed_time_len;
        unsigned char *to;
 
        if (elapsed_time_len == 0)
-               return;
+               return 0;
 
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
-               LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
-                                        "insert elapsed time!\n");
-               return;
-       }
+       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+               return -1;
 
        DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 
@@ -335,521 +372,200 @@ void dccp_insert_option_elapsed_time(struct sock *sk,
        *to++ = len;
 
        if (elapsed_time_len == 2) {
-               const u16 var16 = htons((u16)elapsed_time);
+               const __be16 var16 = htons((u16)elapsed_time);
                memcpy(to, &var16, 2);
        } else {
-               const u32 var32 = htonl(elapsed_time);
+               const __be32 var32 = htonl(elapsed_time);
                memcpy(to, &var32, 4);
        }
 
-       dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
-                     debug_prefix, elapsed_time,
-                     len,
-                     (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
+       return 0;
 }
 
 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
 
-static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
-{
-       struct dccp_sock *dp = dccp_sk(sk);
-#ifdef CONFIG_IP_DCCP_DEBUG
-       const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                       "CLIENT TX opt: " : "server TX opt: ";
-#endif
-       struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
-       int len = ap->dccpap_buf_vector_len + 2;
-       const u32 elapsed_time = timeval_now_delta(&ap->dccpap_time) / 10;
-       unsigned char *to, *from;
-
-       if (elapsed_time != 0)
-               dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
-
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
-               LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
-                                        "insert ACK Vector!\n");
-               return;
-       }
-
-       /*
-        * XXX: now we have just one ack vector sent record, so
-        * we have to wait for it to be cleared.
-        *
-        * Of course this is not acceptable, but this is just for
-        * basic testing now.
-        */
-       if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1)
-               return;
-
-       DCCP_SKB_CB(skb)->dccpd_opt_len += len;
-
-       to    = skb_push(skb, len);
-       *to++ = DCCPO_ACK_VECTOR_0;
-       *to++ = len;
-
-       len  = ap->dccpap_buf_vector_len;
-       from = ap->dccpap_buf + ap->dccpap_buf_head;
-
-       /* Check if buf_head wraps */
-       if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) {
-               const unsigned int tailsize = (ap->dccpap_buf_len -
-                                              ap->dccpap_buf_head);
-
-               memcpy(to, from, tailsize);
-               to   += tailsize;
-               len  -= tailsize;
-               from = ap->dccpap_buf;
-       }
-
-       memcpy(to, from, len);
-       /*
-        *      From draft-ietf-dccp-spec-11.txt:
-        *
-        *      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.
-        *
-        * This implemention uses just one ack record for now.
-        */
-       ap->dccpap_ack_seqno      = DCCP_SKB_CB(skb)->dccpd_seq;
-       ap->dccpap_ack_ptr        = ap->dccpap_buf_head;
-       ap->dccpap_ack_ackno      = ap->dccpap_buf_ackno;
-       ap->dccpap_ack_nonce      = ap->dccpap_buf_nonce;
-       ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len;
-
-       dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
-                     "ack_ackno=%llu\n",
-                     debug_prefix, ap->dccpap_ack_vector_len,
-                     (unsigned long long) ap->dccpap_ack_seqno,
-                     (unsigned long long) ap->dccpap_ack_ackno);
-}
-
-void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
+int dccp_insert_option_timestamp(struct sk_buff *skb)
 {
-       struct timeval tv;
-       u32 now;
-       
-       do_gettimeofday(&tv);
-       now = (tv.tv_sec * USEC_PER_SEC + tv.tv_usec) / 10;
+       __be32 now = htonl(dccp_timestamp());
        /* yes this will overflow but that is the point as we want a
         * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
 
-       now = htonl(now);
-       dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
+       return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
 }
 
 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
 
-static void dccp_insert_option_timestamp_echo(struct sock *sk,
-                                             struct sk_buff *skb)
+static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
+                                            struct dccp_request_sock *dreq,
+                                            struct sk_buff *skb)
 {
-       struct dccp_sock *dp = dccp_sk(sk);
-#ifdef CONFIG_IP_DCCP_DEBUG
-       const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                       "CLIENT TX opt: " : "server TX opt: ";
-#endif
-       u32 tstamp_echo;
-       const u32 elapsed_time =
-                       timeval_now_delta(&dp->dccps_timestamp_time) / 10;
-       const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
-       const int len = 6 + elapsed_time_len;
+       __be32 tstamp_echo;
        unsigned char *to;
+       u32 elapsed_time, elapsed_time_len, len;
 
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
-               LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
-                                        "timestamp echo!\n");
-               return;
+       if (dreq != NULL) {
+               elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
+               tstamp_echo  = htonl(dreq->dreq_timestamp_echo);
+               dreq->dreq_timestamp_echo = 0;
+       } else {
+               elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
+               tstamp_echo  = htonl(dp->dccps_timestamp_echo);
+               dp->dccps_timestamp_echo = 0;
        }
 
+       elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
+       len = 6 + elapsed_time_len;
+
+       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);
        *to++ = DCCPO_TIMESTAMP_ECHO;
        *to++ = len;
 
-       tstamp_echo = htonl(dp->dccps_timestamp_echo);
        memcpy(to, &tstamp_echo, 4);
        to += 4;
-       
+
        if (elapsed_time_len == 2) {
-               const u16 var16 = htons((u16)elapsed_time);
+               const __be16 var16 = htons((u16)elapsed_time);
                memcpy(to, &var16, 2);
        } else if (elapsed_time_len == 4) {
-               const u32 var32 = htonl(elapsed_time);
+               const __be32 var32 = htonl(elapsed_time);
                memcpy(to, &var32, 4);
        }
 
-       dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
-                     debug_prefix, dp->dccps_timestamp_echo,
-                     len,
-                     (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
-
-       dp->dccps_timestamp_echo = 0;
-       dp->dccps_timestamp_time.tv_sec = 0;
-       dp->dccps_timestamp_time.tv_usec = 0;
+       return 0;
 }
 
-void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
+/**
+ * dccp_insert_option_mandatory  -  Mandatory option (5.8.2)
+ * Note that since we are using skb_push, this function needs to be called
+ * _after_ inserting the option it is supposed to influence (stack order).
+ */
+int dccp_insert_option_mandatory(struct sk_buff *skb)
 {
-       struct dccp_sock *dp = dccp_sk(sk);
+       if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
+               return -1;
 
-       DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
-
-       if (dp->dccps_options.dccpo_send_ndp_count)
-               dccp_insert_option_ndp(sk, skb);
+       DCCP_SKB_CB(skb)->dccpd_opt_len++;
+       *skb_push(skb, 1) = DCCPO_MANDATORY;
+       return 0;
+}
 
-       if (!dccp_packet_without_ack(skb)) {
-               if (dp->dccps_options.dccpo_send_ack_vector &&
-                   (dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno !=
-                    DCCP_MAX_SEQNO + 1))
-                       dccp_insert_option_ack_vector(sk, skb);
+/**
+ * dccp_insert_fn_opt  -  Insert single Feature-Negotiation option into @skb
+ * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
+ * @feat: one out of %dccp_feature_numbers
+ * @val: NN value or SP array (preferred element first) to copy
+ * @len: true length of @val in bytes (excluding first element repetition)
+ * @repeat_first: whether to copy the first element of @val twice
+ * The last argument is used to construct Confirm options, where the preferred
+ * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
+ * lists are kept such that the preferred entry is always first, so we only need
+ * to copy twice, and avoid the overhead of cloning into a bigger array.
+ */
+int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
+                      u8 *val, u8 len, bool repeat_first)
+{
+       u8 tot_len, *to;
 
-               if (dp->dccps_timestamp_echo != 0)
-                       dccp_insert_option_timestamp_echo(sk, skb);
+       /* take the `Feature' field and possible repetition into account */
+       if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
+               DCCP_WARN("length %u for feature %u too large\n", len, feat);
+               return -1;
        }
 
-       ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
-       ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
-
-       /* XXX: insert other options when appropriate */
-
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
-               /* The length of all options has to be a multiple of 4 */
-               int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
-
-               if (padding != 0) {
-                       padding = 4 - padding;
-                       memset(skb_push(skb, padding), 0, padding);
-                       DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
-               }
-       }
-}
+       if (unlikely(val == NULL || len == 0))
+               len = repeat_first = 0;
+       tot_len = 3 + repeat_first + len;
 
-struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
-                                       const unsigned int __nocast priority)
-{
-       struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority);
-
-       if (ap != NULL) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-               memset(ap->dccpap_buf, 0xFF, len);
-#endif
-               ap->dccpap_buf_len   = len;
-               ap->dccpap_buf_head  =
-                       ap->dccpap_buf_tail =
-                               ap->dccpap_buf_len - 1;
-               ap->dccpap_buf_ackno =
-                       ap->dccpap_ack_ackno =
-                               ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-               ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
-               ap->dccpap_ack_ptr   = 0;
-               ap->dccpap_time.tv_sec = 0;
-               ap->dccpap_time.tv_usec = 0;
-               ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
+       if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
+               DCCP_WARN("packet too small for feature %d option!\n", feat);
+               return -1;
        }
+       DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
 
-       return ap;
-}
+       to    = skb_push(skb, tot_len);
+       *to++ = type;
+       *to++ = tot_len;
+       *to++ = feat;
 
-void dccp_ackpkts_free(struct dccp_ackpkts *ap)
-{
-       if (ap != NULL) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-               memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len);
-#endif
-               kfree(ap);
-       }
+       if (repeat_first)
+               *to++ = *val;
+       if (len)
+               memcpy(to, val, len);
+       return 0;
 }
 
-static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap,
-                                   const unsigned int index)
+/* The length of all options needs to be a multiple of 4 (5.8) */
+static void dccp_insert_option_padding(struct sk_buff *skb)
 {
-       return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK;
-}
+       int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
 
-static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap,
-                                 const unsigned int index)
-{
-       return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK;
+       if (padding != 0) {
+               padding = 4 - padding;
+               memset(skb_push(skb, padding), 0, padding);
+               DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
+       }
 }
 
-/*
- * 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;
- * this simplifies table updates if one of the missing packets arrives.
- */
-static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap,
-                                                 const unsigned int packets,
-                                                 const unsigned char state)
+int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 {
-       unsigned int gap;
-       signed long new_head;
-
-       if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len)
-               return -ENOBUFS;
-
-       gap      = packets - 1;
-       new_head = ap->dccpap_buf_head - packets;
-
-       if (new_head < 0) {
-               if (gap > 0) {
-                       memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED,
-                              gap + new_head + 1);
-                       gap = -new_head;
-               }
-               new_head += ap->dccpap_buf_len;
-       } 
+       struct dccp_sock *dp = dccp_sk(sk);
 
-       ap->dccpap_buf_head = new_head;
+       DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 
-       if (gap > 0)
-               memset(ap->dccpap_buf + ap->dccpap_buf_head + 1,
-                      DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap);
+       if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
+               return -1;
 
-       ap->dccpap_buf[ap->dccpap_buf_head] = state;
-       ap->dccpap_buf_vector_len += packets;
-       return 0;
-}
+       if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
 
-/*
- * Implements the draft-ietf-dccp-spec-11.txt Appendix A
- */
-int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state)
-{
-       /*
-        * 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
-        * vectors, when we will free up space in dccpap_buf.
-        *
-        * We may well decide to do buffer compression, etc, but for now lets
-        * just drop.
-        *
-        * From Appendix A:
-        *
-        *      Of course, the circular buffer may overflow, either when the
-        *      HC-Sender is sending data at a very high rate, when the
-        *      HC-Receiver's acknowledgements are not reaching the HC-Sender,
-        *      or when the HC-Sender is forgetting to acknowledge those acks
-        *      (so the HC-Receiver is unable to clean up old state). In this
-        *      case, the HC-Receiver should either compress the buffer (by
-        *      increasing run lengths when possible), transfer its state to
-        *      a larger buffer, or, as a last resort, drop all received
-        *      packets, without processing them whatsoever, until its buffer
-        *      shrinks again.
-        */
-
-       /* See if this is the first ackno being inserted */
-       if (ap->dccpap_buf_vector_len == 0) {
-               ap->dccpap_buf[ap->dccpap_buf_head] = state;
-               ap->dccpap_buf_vector_len = 1;
-       } else if (after48(ackno, ap->dccpap_buf_ackno)) {
-               const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno,
-                                                  ackno);
+               /* Feature Negotiation */
+               if (dccp_feat_insert_opts(dp, NULL, skb))
+                       return -1;
 
-               /*
-                * 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_ackpkts_state(ap, ap->dccpap_buf_head) == state &&
-                   (dccp_ackpkts_len(ap, ap->dccpap_buf_head) <
-                    DCCP_ACKPKTS_LEN_MASK))
-                       ap->dccpap_buf[ap->dccpap_buf_head]++;
-               else if (dccp_ackpkts_set_buf_head_state(ap, delta, state))
-                       return -ENOBUFS;
-       } else {
-               /*
-                * A.1.2.  Old Packets
-                *
-                *      When a packet with Sequence Number S arrives, and
-                *      S <= buf_ackno, the HC-Receiver will scan the table
-                *      for the byte corresponding to S. (Indexing structures
-                *      could reduce the complexity of this scan.)
-                */
-               u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno);
-               unsigned int index = ap->dccpap_buf_head;
-
-               while (1) {
-                       const u8 len = dccp_ackpkts_len(ap, index);
-                       const u8 state = dccp_ackpkts_state(ap, index);
+               if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
                        /*
-                        * valid packets not yet in dccpap_buf have a reserved
-                        * entry, with a len equal to 0.
+                        * Obtain RTT sample from Request/Response exchange.
+                        * This is currently used in CCID 3 initialisation.
                         */
-                       if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED &&
-                           len == 0 && delta == 0) { /* Found our
-                                                        reserved seat! */
-                               dccp_pr_debug("Found %llu reserved seat!\n",
-                                             (unsigned long long) ackno);
-                               ap->dccpap_buf[index] = state;
-                               goto out;
-                       }
-                       /* len == 0 means one packet */
-                       if (delta < len + 1)
-                               goto out_duplicate;
+                       if (dccp_insert_option_timestamp(skb))
+                               return -1;
 
-                       delta -= len + 1;
-                       if (++index == ap->dccpap_buf_len)
-                               index = 0;
+               } else if (dp->dccps_hc_rx_ackvec != NULL &&
+                          dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
+                          dccp_insert_option_ackvec(sk, skb)) {
+                               return -1;
                }
        }
 
-       ap->dccpap_buf_ackno = ackno;
-       do_gettimeofday(&ap->dccpap_time);
-out:
-       dccp_pr_debug("");
-       dccp_ackpkts_print(ap);
-       return 0;
-
-out_duplicate:
-       /* Duplicate packet */
-       dccp_pr_debug("Received a dup or already considered lost "
-                     "packet: %llu\n", (unsigned long long) ackno);
-       return -EILSEQ;
-}
-
-#ifdef CONFIG_IP_DCCP_DEBUG
-void dccp_ackvector_print(const u64 ackno, const unsigned char *vector,
-                         int len)
-{
-       if (!dccp_debug)
-               return;
-
-       printk("ACK vector len=%d, ackno=%llu |", len,
-              (unsigned long long) ackno);
-
-       while (len--) {
-               const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6;
-               const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
-
-               printk("%d,%d|", state, rl);
-               ++vector;
+       if (dp->dccps_hc_rx_insert_options) {
+               if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
+                       return -1;
+               dp->dccps_hc_rx_insert_options = 0;
        }
 
-       printk("\n");
-}
+       if (dp->dccps_timestamp_echo != 0 &&
+           dccp_insert_option_timestamp_echo(dp, NULL, skb))
+               return -1;
 
-void dccp_ackpkts_print(const struct dccp_ackpkts *ap)
-{
-       dccp_ackvector_print(ap->dccpap_buf_ackno,
-                            ap->dccpap_buf + ap->dccpap_buf_head,
-                            ap->dccpap_buf_vector_len);
-}
-#endif
-
-static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap)
-{
-       /*
-        * As we're keeping track of the ack vector size
-        * (dccpap_buf_vector_len) and the sent ack vector size
-        * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but
-        * keep this code here as in the future we'll implement a vector of
-        * ack records, as suggested in draft-ietf-dccp-spec-11.txt
-        * Appendix A. -acme
-        */
-#if 0
-       ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1;
-       if (ap->dccpap_buf_tail >= ap->dccpap_buf_len)
-               ap->dccpap_buf_tail -= ap->dccpap_buf_len;
-#endif
-       ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len;
-}
-
-void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk,
-                                u64 ackno)
-{
-       /* Check if we actually sent an ACK vector */
-       if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
-               return;
-
-       if (ackno == ap->dccpap_ack_seqno) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-               struct dccp_sock *dp = dccp_sk(sk);
-               const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                       "CLIENT rx ack: " : "server rx ack: ";
-#endif
-               dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
-                             "ack_ackno=%llu, ACKED!\n",
-                             debug_prefix, 1,
-                             (unsigned long long) ap->dccpap_ack_seqno,
-                             (unsigned long long) ap->dccpap_ack_ackno);
-               dccp_ackpkts_trow_away_ack_record(ap);
-               ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-       }
+       dccp_insert_option_padding(skb);
+       return 0;
 }
 
-static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
-                                            struct sock *sk, u64 ackno,
-                                            const unsigned char len,
-                                            const unsigned char *vector)
+int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
 {
-       unsigned char i;
-
-       /* Check if we actually sent an ACK vector */
-       if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
-               return;
-       /*
-        * We're in the receiver half connection, so if the received an ACK
-        * vector ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're
-        * not interested.
-        *
-        * Extra explanation with example:
-        * 
-        * if we received an ACK vector with ackno 50, it can only be acking
-        * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
-        */
-       /* dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); */
-       if (before48(ackno, ap->dccpap_ack_seqno)) {
-               /* dccp_pr_debug_cat("yes\n"); */
-               return;
-       }
-       /* dccp_pr_debug_cat("no\n"); */
+       DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 
-       i = len;
-       while (i--) {
-               const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
-               u64 ackno_end_rl;
+       if (dccp_feat_insert_opts(NULL, dreq, skb))
+               return -1;
 
-               dccp_set_seqno(&ackno_end_rl, ackno - rl);
+       if (dreq->dreq_timestamp_echo != 0 &&
+           dccp_insert_option_timestamp_echo(NULL, dreq, skb))
+               return -1;
 
-               /*
-                * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
-                * ap->dccpap_ack_seqno, ackno);
-                */
-               if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) {
-                       const u8 state = (*vector &
-                                         DCCP_ACKPKTS_STATE_MASK) >> 6;
-                       /* dccp_pr_debug_cat("yes\n"); */
-
-                       if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-                               struct dccp_sock *dp = dccp_sk(sk);
-                               const char *debug_prefix =
-                                       dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                       "CLIENT rx ack: " : "server rx ack: ";
-#endif
-                               dccp_pr_debug("%sACK vector 0, len=%d, "
-                                             "ack_seqno=%llu, ack_ackno=%llu, "
-                                             "ACKED!\n",
-                                             debug_prefix, len,
-                                             (unsigned long long)
-                                             ap->dccpap_ack_seqno,
-                                             (unsigned long long)
-                                             ap->dccpap_ack_ackno);
-                               dccp_ackpkts_trow_away_ack_record(ap);
-                       }
-                       /*
-                        * If dccpap_ack_seqno was not received, no problem
-                        * we'll send another ACK vector.
-                        */
-                       ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-                       break;
-               }
-               /* dccp_pr_debug_cat("no\n"); */
-
-               dccp_set_seqno(&ackno, ackno_end_rl - 1);
-               ++vector;
-       }
+       dccp_insert_option_padding(skb);
+       return 0;
 }