/* * 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" int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW; int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID; int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID; int sysctl_dccp_feat_ack_ratio = DCCPF_INITIAL_ACK_RATIO; int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR; int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_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; } /** * 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; 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; 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_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; } /* * 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) goto out_invalid_option; opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk), opt_recv->dccpor_ndp); break; case DCCPO_CHANGE_L: /* fall through */ case DCCPO_CHANGE_R: if (pkt_type == DCCP_PKT_DATA) break; 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 (pkt_type == DCCP_PKT_DATA) break; if (len < 2) /* FIXME this disallows empty confirm */ 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 (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */ break; if (dccp_msk(sk)->dccpms_send_ack_vector && dccp_ackvec_parse(sk, skb, &ackno, opt, value, len)) goto out_invalid_option; 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); 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 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: 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; return 0; out_invalid_option: DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; DCCP_WARN("DCCP(%p): invalid option %d, len=%d", 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); 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_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) { DCCP_WARN("packet too small for 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("%s(%s (%d), ...), length %d\n", dccp_feat_typename(type), dccp_feat_name(feat), 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; } /* 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); 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_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; } /* 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; /* * Obtain RTT sample from Request/Response exchange. * This is currently used in CCID 3 initialisation. */ if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST && dccp_insert_option_timestamp(sk, skb)) return -1; 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 (dreq->dreq_timestamp_echo != 0 && dccp_insert_option_timestamp_echo(NULL, dreq, skb)) return -1; dccp_insert_option_padding(skb); return 0; }