diff options
Diffstat (limited to 'net/dccp/options.c')
| -rw-r--r-- | net/dccp/options.c | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/net/dccp/options.c b/net/dccp/options.c new file mode 100644 index 000000000000..0a76426c9aea --- /dev/null +++ b/net/dccp/options.c @@ -0,0 +1,462 @@ +/* + * 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" + +/* 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_rx_ccid = DCCPF_INITIAL_CCID, + .dccpo_tx_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) +{ + memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo)); +} + +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; + + memset(opt_recv, 0, sizeof(*opt_recv)); + + 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_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_ACK_VECTOR_0: + case DCCPO_ACK_VECTOR_1: + if (pkt_type == DCCP_PKT_DATA) + continue; + + if (dp->dccps_options.dccpo_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(*(u32 *)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(*(u32 *)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(*(u16 *)(value + 4)); + else + elapsed_time = ntohl(*(u32 *)(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(*(u16 *)value); + else + 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, + 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; + } + } + + 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; +} + +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; +} + +void 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) { + LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert " + "%d option!\n", option); + return; + } + + DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; + + to = skb_push(skb, len + 2); + *to++ = option; + *to++ = len + 2; + + memcpy(to, value, len); +} + +EXPORT_SYMBOL_GPL(dccp_insert_option); + +static void 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; + + 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); + } +} + +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) +{ +#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; + + 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; + } + + 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 u16 var16 = htons((u16)elapsed_time); + memcpy(to, &var16, 2); + } else { + const u32 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); +} + +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); + +void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) +{ + struct timeval tv; + u32 now; + + dccp_timestamp(sk, &tv); + now = 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 */ + + now = htonl(now); + dccp_insert_option(sk, 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) +{ + 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 timeval now; + u32 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) { + LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert " + "timestamp echo!\n"); + return; + } + + 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); + memcpy(to, &var16, 2); + } else if (elapsed_time_len == 4) { + const u32 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; +} + +void 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_options.dccpo_send_ndp_count) + dccp_insert_option_ndp(sk, skb); + + if (!dccp_packet_without_ack(skb)) { + if (dp->dccps_options.dccpo_send_ack_vector && + dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) + dccp_insert_option_ackvec(sk, skb); + if (dp->dccps_timestamp_echo != 0) + dccp_insert_option_timestamp_echo(sk, skb); + } + + if (dp->dccps_hc_rx_insert_options) { + ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb); + dp->dccps_hc_rx_insert_options = 0; + } + if (dp->dccps_hc_tx_insert_options) { + ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb); + dp->dccps_hc_tx_insert_options = 0; + } + + /* 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; + } + } +} |