| /* |
| * 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 <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/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" |
| |
| u64 dccp_decode_value_var(const u8 *bf, const u8 len) |
| { |
| u64 value = 0; |
| |
| if (len >= DCCP_OPTVAL_MAXLEN) |
| value += ((u64)*bf++) << 40; |
| if (len > 4) |
| value += ((u64)*bf++) << 32; |
| if (len > 3) |
| value += ((u64)*bf++) << 24; |
| if (len > 2) |
| value += ((u64)*bf++) << 16; |
| if (len > 1) |
| value += ((u64)*bf++) << 8; |
| if (len > 0) |
| value += *bf; |
| |
| return value; |
| } |
| |
| /** |
| * 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); |
| 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; |
| __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; |
| value = NULL; |
| |
| /* Check if this isn't a single byte option */ |
| if (opt > DCCPO_MAX_RESERVED) { |
| if (opt_ptr == opt_end) |
| goto out_nonsensical_length; |
| |
| len = *opt_ptr++; |
| if (len < 2) |
| goto out_nonsensical_length; |
| /* |
| * 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_nonsensical_length; |
| } |
| |
| /* |
| * 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 >= DCCPO_MIN_RX_CCID_SPECIFIC || |
| 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 > 6) |
| goto out_invalid_option; |
| |
| opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); |
| 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: |
| case DCCPO_ACK_VECTOR_1: |
| if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */ |
| break; |
| dccp_pr_debug("%s Ack Vector (len=%u)\n", dccp_role(sk), |
| len); |
| 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; |
| } |
| |
| 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); |
| /* schedule an Ack in case this sender is quiescent */ |
| inet_csk_schedule_ack(sk); |
| break; |
| case DCCPO_TIMESTAMP_ECHO: |
| if (len != 4 && len != 6 && len != 8) |
| goto out_invalid_option; |
| |
| opt_val = get_unaligned((__be32 *)value); |
| opt_recv->dccpor_timestamp_echo = ntohl(opt_val); |
| |
| 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); |
| |
| 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 (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 (elapsed_time > opt_recv->dccpor_elapsed_time) |
| opt_recv->dccpor_elapsed_time = elapsed_time; |
| |
| dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", |
| dccp_role(sk), elapsed_time); |
| break; |
| case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC: |
| if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, |
| pkt_type, opt, value, len)) |
| goto out_invalid_option; |
| break; |
| case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC: |
| if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, |
| pkt_type, opt, value, len)) |
| goto out_invalid_option; |
| break; |
| default: |
| 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); |
| 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; |
| } |
| |
| 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) |
| *to++ = (value & 0xFF0000) >> 16; |
| if (len > 1) |
| *to++ = (value & 0xFF00) >> 8; |
| if (len > 0) |
| *to++ = (value & 0xFF); |
| } |
| |
| static inline u8 dccp_ndp_len(const u64 ndp) |
| { |
| if (likely(ndp <= 0xFF)) |
| return 1; |
| return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6); |
| } |
| |
| 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); |
| u64 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); |
| |
| int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) |
| { |
| __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 */ |
| |
| 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 dccp_sock *dp, |
| struct dccp_request_sock *dreq, |
| struct sk_buff *skb) |
| { |
| __be32 tstamp_echo; |
| unsigned char *to; |
| u32 elapsed_time, elapsed_time_len, len; |
| |
| 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; |
| |
| 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); |
| } |
| |
| return 0; |
| } |
| |
| static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; |
| const u16 buflen = dccp_ackvec_buflen(av); |
| /* Figure out how many options do we need to represent the ackvec */ |
| const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN); |
| u16 len = buflen + 2 * nr_opts; |
| u8 i, nonce = 0; |
| const unsigned char *tail, *from; |
| unsigned char *to; |
| |
| 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); |
| len = buflen; |
| from = av->av_buf + av->av_buf_head; |
| tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN; |
| |
| for (i = 0; i < nr_opts; ++i) { |
| int copylen = len; |
| |
| if (len > DCCP_SINGLE_OPT_MAXLEN) |
| copylen = DCCP_SINGLE_OPT_MAXLEN; |
| |
| /* |
| * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via |
| * its type; ack_nonce is the sum of all individual buf_nonce's. |
| */ |
| nonce ^= av->av_buf_nonce[i]; |
| |
| *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i]; |
| *to++ = copylen + 2; |
| |
| /* Check if buf_head wraps */ |
| if (from + copylen > tail) { |
| const u16 tailsize = tail - from; |
| |
| memcpy(to, from, tailsize); |
| to += tailsize; |
| len -= tailsize; |
| copylen -= tailsize; |
| from = av->av_buf; |
| } |
| |
| memcpy(to, from, copylen); |
| from += copylen; |
| to += copylen; |
| len -= copylen; |
| } |
| /* |
| * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340. |
| */ |
| if (dccp_ackvec_update_records(av, DCCP_SKB_CB(skb)->dccpd_seq, nonce)) |
| return -ENOBUFS; |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN) |
| return -1; |
| |
| DCCP_SKB_CB(skb)->dccpd_opt_len++; |
| *skb_push(skb, 1) = DCCPO_MANDATORY; |
| return 0; |
| } |
| |
| /** |
| * 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; |
| |
| /* 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; |
| } |
| |
| if (unlikely(val == NULL || len == 0)) |
| len = repeat_first = 0; |
| tot_len = 3 + repeat_first + len; |
| |
| 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; |
| |
| to = skb_push(skb, tot_len); |
| *to++ = type; |
| *to++ = tot_len; |
| *to++ = feat; |
| |
| if (repeat_first) |
| *to++ = *val; |
| if (len) |
| memcpy(to, val, len); |
| return 0; |
| } |
| |
| /* The length of all options needs to be a multiple of 4 (5.8) */ |
| static void dccp_insert_option_padding(struct sk_buff *skb) |
| { |
| 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; |
| } |
| } |
| |
| int dccp_insert_options(struct sock *sk, struct sk_buff *skb) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| |
| DCCP_SKB_CB(skb)->dccpd_opt_len = 0; |
| |
| if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb)) |
| return -1; |
| |
| if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) { |
| |
| /* Feature Negotiation */ |
| if (dccp_feat_insert_opts(dp, NULL, skb)) |
| return -1; |
| |
| if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) { |
| /* |
| * Obtain RTT sample from Request/Response exchange. |
| * This is currently used in CCID 3 initialisation. |
| */ |
| if (dccp_insert_option_timestamp(sk, skb)) |
| return -1; |
| |
| } else if (dccp_ackvec_pending(sk) && |
| dccp_insert_option_ackvec(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_timestamp_echo != 0 && |
| dccp_insert_option_timestamp_echo(dp, NULL, skb)) |
| return -1; |
| |
| dccp_insert_option_padding(skb); |
| return 0; |
| } |
| |
| int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb) |
| { |
| DCCP_SKB_CB(skb)->dccpd_opt_len = 0; |
| |
| if (dccp_feat_insert_opts(NULL, dreq, skb)) |
| return -1; |
| |
| if (dreq->dreq_timestamp_echo != 0 && |
| dccp_insert_option_timestamp_echo(NULL, dreq, skb)) |
| return -1; |
| |
| dccp_insert_option_padding(skb); |
| return 0; |
| } |