--- /dev/null
+/*
+ * net/dccp/options.c
+ *
+ * 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>
+ *
+ * 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 <linux/kernel.h>
+#include <linux/skbuff.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+#include "feat.h"
+
+int dccp_feat_default_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
+int dccp_feat_default_rx_ccid = DCCPF_INITIAL_CCID;
+int dccp_feat_default_tx_ccid = DCCPF_INITIAL_CCID;
+int dccp_feat_default_ack_ratio = DCCPF_INITIAL_ACK_RATIO;
+int dccp_feat_default_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
+int dccp_feat_default_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT;
+
+void dccp_minisock_init(struct dccp_minisock *dmsk)
+{
+ dmsk->dccpms_sequence_window = dccp_feat_default_sequence_window;
+ dmsk->dccpms_rx_ccid = dccp_feat_default_rx_ccid;
+ dmsk->dccpms_tx_ccid = dccp_feat_default_tx_ccid;
+ dmsk->dccpms_ack_ratio = dccp_feat_default_ack_ratio;
+ dmsk->dccpms_send_ack_vector = dccp_feat_default_send_ack_vector;
+ dmsk->dccpms_send_ndp_count = dccp_feat_default_send_ndp_count;
+}
+
+static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
+{
+ u32 value = 0;
+
+ if (len > 3)
+ value += *bf++ << 24;
+ if (len > 2)
+ value += *bf++ << 16;
+ if (len > 1)
+ value += *bf++ << 8;
+ if (len > 0)
+ value += *bf;
+
+ return value;
+}
+
+int dccp_parse_options(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 rx opt: " : "server rx opt: ";
+#endif
+ const struct dccp_hdr *dh = dccp_hdr(skb);
+ const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
+ 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;
+ u32 elapsed_time;
+ 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;
+ 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_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)
+ 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);
+ break;
+ case DCCPO_CHANGE_L:
+ /* fall through */
+ case DCCPO_CHANGE_R:
+ if (len < 2)
+ goto out_invalid_option;
+ rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
+ len - 1);
+ /*
+ * When there is a change error, change_recv is
+ * responsible for dealing with it. i.e. reply with an
+ * empty confirm.
+ * If the change was mandatory, then we need to die.
+ */
+ if (rc && mandatory)
+ goto out_invalid_option;
+ break;
+ case DCCPO_CONFIRM_L:
+ /* fall through */
+ case DCCPO_CONFIRM_R:
+ if (len < 2)
+ goto out_invalid_option;
+ if (dccp_feat_confirm_recv(sk, opt, *value,
+ value + 1, len - 1))
+ goto out_invalid_option;
+ break;
+ case DCCPO_ACK_VECTOR_0:
+ case DCCPO_ACK_VECTOR_1:
+ if (pkt_type == DCCP_PKT_DATA)
+ break;
+
+ if (dccp_msk(sk)->dccpms_send_ack_vector &&
+ dccp_ackvec_parse(sk, skb, opt, value, len))
+ goto out_invalid_option;
+ break;
+ case DCCPO_TIMESTAMP:
+ if (len != 4)
+ goto out_invalid_option;
+
+ opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
+
+ dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
+ dccp_timestamp(sk, &dp->dccps_timestamp_time);
+
+ dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
+ debug_prefix, opt_recv->dccpor_timestamp,
+ (unsigned long long)
+ DCCP_SKB_CB(skb)->dccpd_ack_seq);
+ break;
+ case DCCPO_TIMESTAMP_ECHO:
+ if (len != 4 && len != 6 && len != 8)
+ goto out_invalid_option;
+
+ opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
+
+ dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
+ debug_prefix,
+ opt_recv->dccpor_timestamp_echo,
+ len + 2,
+ (unsigned long long)
+ DCCP_SKB_CB(skb)->dccpd_ack_seq);
+
+
+ if (len == 4)
+ break;
+
+ if (len == 6)
+ elapsed_time = ntohs(*(__be16 *)(value + 4));
+ else
+ elapsed_time = ntohl(*(__be32 *)(value + 4));
+
+ /* 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)
+ goto out_invalid_option;
+
+ if (pkt_type == DCCP_PKT_DATA)
+ continue;
+
+ if (len == 2)
+ elapsed_time = ntohs(*(__be16 *)value);
+ else
+ elapsed_time = ntohl(*(__be32 *)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,
+ 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;
+
+ if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
+ opt, len, idx,
+ value) != 0)
+ goto out_invalid_option;
+ }
+ break;
+ case 192 ... 255: {
+ const u16 idx = value - options;
+
+ if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
+ opt, len, idx,
+ value) != 0)
+ goto out_invalid_option;
+ }
+ break;
+ default:
+ pr_info("DCCP(%p): option %d(len=%d) not "
+ "implemented, ignoring\n",
+ sk, opt, len);
+ break;
+ }
+
+ if (opt != DCCPO_MANDATORY)
+ mandatory = 0;
+ }
+
+ /* mandatory was the last byte in option list -> reset connection */
+ if (mandatory)
+ goto out_invalid_option;
+
+ 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);
+ return -1;
+}
+
+EXPORT_SYMBOL_GPL(dccp_parse_options);
+
+static void dccp_encode_value_var(const u32 value, unsigned char *to,
+ const unsigned int len)
+{
+ if (len > 3)
+ *to++ = (value & 0xFF000000) >> 24;
+ if (len > 2)
+ *to++ = (value & 0xFF0000) >> 16;
+ if (len > 1)
+ *to++ = (value & 0xFF00) >> 8;
+ if (len > 0)
+ *to++ = (value & 0xFF);
+}
+
+static inline int dccp_ndp_len(const int ndp)
+{
+ return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
+}
+
+int dccp_insert_option(struct sock *sk, 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)
+ return -1;
+
+ DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
+
+ to = skb_push(skb, len + 2);
+ *to++ = option;
+ *to++ = len + 2;
+
+ memcpy(to, value, len);
+ return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_insert_option);
+
+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;
+
+ if (dccp_non_data_packet(skb))
+ ++dp->dccps_ndp_count;
+ else
+ dp->dccps_ndp_count = 0;
+
+ if (ndp > 0) {
+ unsigned char *ptr;
+ const int ndp_len = dccp_ndp_len(ndp);
+ const int len = ndp_len + 2;
+
+ if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+ return -1;
+
+ DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+ ptr = skb_push(skb, len);
+ *ptr++ = DCCPO_NDP_COUNT;
+ *ptr++ = len;
+ dccp_encode_value_var(ndp, ptr, ndp_len);
+ }
+
+ return 0;
+}
+
+static inline int dccp_elapsed_time_len(const u32 elapsed_time)
+{
+ return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
+}
+
+int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
+ u32 elapsed_time)
+{
+ 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 0;
+
+ 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_ELAPSED_TIME;
+ *to++ = len;
+
+ if (elapsed_time_len == 2) {
+ const __be16 var16 = htons((u16)elapsed_time);
+ memcpy(to, &var16, 2);
+ } else {
+ const __be32 var32 = htonl(elapsed_time);
+ memcpy(to, &var32, 4);
+ }
+
+ return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
+
+void dccp_timestamp(const struct sock *sk, struct timeval *tv)
+{
+ const struct dccp_sock *dp = dccp_sk(sk);
+
+ do_gettimeofday(tv);
+ tv->tv_sec -= dp->dccps_epoch.tv_sec;
+ tv->tv_usec -= dp->dccps_epoch.tv_usec;
+
+ while (tv->tv_usec < 0) {
+ tv->tv_sec--;
+ tv->tv_usec += USEC_PER_SEC;
+ }
+}
+
+EXPORT_SYMBOL_GPL(dccp_timestamp);
+
+int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
+{
+ struct timeval tv;
+ __be32 now;
+
+ dccp_timestamp(sk, &tv);
+ now = htonl(timeval_usecs(&tv) / 10);
+ /* 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 */
+
+ return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
+}
+
+EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
+
+static int dccp_insert_option_timestamp_echo(struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct timeval now;
+ __be32 tstamp_echo;
+ u32 elapsed_time;
+ int len, elapsed_time_len;
+ unsigned char *to;
+
+ dccp_timestamp(sk, &now);
+ elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
+ 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 __be16 var16 = htons((u16)elapsed_time);
+ memcpy(to, &var16, 2);
+ } else if (elapsed_time_len == 4) {
+ const __be32 var32 = htonl(elapsed_time);
+ memcpy(to, &var32, 4);
+ }
+
+ dp->dccps_timestamp_echo = 0;
+ dp->dccps_timestamp_time.tv_sec = 0;
+ dp->dccps_timestamp_time.tv_usec = 0;
+ return 0;
+}
+
+static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
+ u8 *val, u8 len)
+{
+ u8 *to;
+
+ if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
+ LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small"
+ " to insert feature %d option!\n", feat);
+ return -1;
+ }
+
+ DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
+
+ to = skb_push(skb, len + 3);
+ *to++ = type;
+ *to++ = len + 3;
+ *to++ = feat;
+
+ if (len)
+ memcpy(to, val, len);
+ dccp_pr_debug("option %d feat %d len %d\n", type, feat, len);
+
+ return 0;
+}
+
+static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct dccp_minisock *dmsk = dccp_msk(sk);
+ struct dccp_opt_pend *opt, *next;
+ int change = 0;
+
+ /* confirm any options [NN opts] */
+ list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
+ dccp_insert_feat_opt(skb, opt->dccpop_type,
+ opt->dccpop_feat, opt->dccpop_val,
+ opt->dccpop_len);
+ /* fear empty confirms */
+ if (opt->dccpop_val)
+ kfree(opt->dccpop_val);
+ kfree(opt);
+ }
+ INIT_LIST_HEAD(&dmsk->dccpms_conf);
+
+ /* see which features we need to send */
+ list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
+ /* see if we need to send any confirm */
+ if (opt->dccpop_sc) {
+ dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
+ opt->dccpop_feat,
+ opt->dccpop_sc->dccpoc_val,
+ opt->dccpop_sc->dccpoc_len);
+
+ BUG_ON(!opt->dccpop_sc->dccpoc_val);
+ kfree(opt->dccpop_sc->dccpoc_val);
+ kfree(opt->dccpop_sc);
+ opt->dccpop_sc = NULL;
+ }
+
+ /* any option not confirmed, re-send it */
+ if (!opt->dccpop_conf) {
+ dccp_insert_feat_opt(skb, opt->dccpop_type,
+ opt->dccpop_feat, opt->dccpop_val,
+ opt->dccpop_len);
+ change++;
+ }
+ }
+
+ /* Retransmit timer.
+ * If this is the master listening sock, we don't set a timer on it. It
+ * should be fine because if the dude doesn't receive our RESPONSE
+ * [which will contain the CHANGE] he will send another REQUEST which
+ * will "retrnasmit" the change.
+ */
+ if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
+ dccp_pr_debug("reset feat negotiation timer %p\n", sk);
+
+ /* XXX don't reset the timer on re-transmissions. I.e. reset it
+ * only when sending new stuff i guess. Currently the timer
+ * never backs off because on re-transmission it just resets it!
+ */
+ inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+ inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
+ }
+
+ return 0;
+}
+
+int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct dccp_minisock *dmsk = dccp_msk(sk);
+
+ DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
+
+ if (dmsk->dccpms_send_ndp_count &&
+ dccp_insert_option_ndp(sk, skb))
+ return -1;
+
+ if (!dccp_packet_without_ack(skb)) {
+ if (dmsk->dccpms_send_ack_vector &&
+ dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
+ dccp_insert_option_ackvec(sk, skb))
+ return -1;
+
+ if (dp->dccps_timestamp_echo != 0 &&
+ dccp_insert_option_timestamp_echo(sk, skb))
+ return -1;
+ }
+
+ 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;
+ }
+ if (dp->dccps_hc_tx_insert_options) {
+ if (ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb))
+ return -1;
+ dp->dccps_hc_tx_insert_options = 0;
+ }
+
+ /* Feature negotiation */
+ /* Data packets can't do feat negotiation */
+ if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
+ DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
+ dccp_insert_options_feat(sk, skb))
+ return -1;
+
+ /* 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;
+ }
+ }
+
+ return 0;
+}
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