diff options
Diffstat (limited to 'net/dccp/options.c')
| -rw-r--r-- | net/dccp/options.c | 763 |
1 files changed, 763 insertions, 0 deletions
diff --git a/net/dccp/options.c b/net/dccp/options.c new file mode 100644 index 0000000..e186776 --- /dev/null +++ b/net/dccp/options.c @@ -0,0 +1,763 @@ +/* + * net/dccp/options.c + * + * An implementation of the DCCP protocol + * Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org> + * Arnaldo Carvalho de Melo <acme@ghostprotocols.net> + * + * 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 "ccid.h" +#include "dccp.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) +{ + 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 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; + + 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: + if (len > DCCP_MAX_ACK_VECTOR_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, 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; + + opt_recv->dccpor_timestamp = ntohl(*(u32 *)value); + + dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp; + dp->dccps_timestamp_time = jiffies; + + dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n", + debug_prefix, opt_recv->dccpor_timestamp, + DCCP_SKB_CB(skb)->dccpd_ack_seq); + break; + case DCCPO_TIMESTAMP_ECHO: + if (len < 4 || len > 8) + goto out_invalid_option; + + opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value); + + dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, diff=%u\n", + debug_prefix, opt_recv->dccpor_timestamp_echo, + len + 2, DCCP_SKB_CB(skb)->dccpd_ack_seq, + tcp_time_stamp - opt_recv->dccpor_timestamp_echo); + + opt_recv->dccpor_elapsed_time = dccp_decode_value_var(value + 4, len - 4); + dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n", debug_prefix, + opt_recv->dccpor_elapsed_time); + break; + case DCCPO_ELAPSED_TIME: + if (len > 4) + goto out_invalid_option; + + if (pkt_type == DCCP_PKT_DATA) + continue; + opt_recv->dccpor_elapsed_time = dccp_decode_value_var(value, len); + dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix, + opt_recv->dccpor_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(pr_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 <= 0xFF ? 1 : + elapsed_time <= 0xFFFF ? 2 : + elapsed_time <= 0xFFFFFF ? 3 : 4; +} + +void dccp_insert_option_elapsed_time(struct sock *sk, + struct sk_buff *skb, + u32 elapsed_time) +{ +#ifdef 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 == 0... */ + if (elapsed_time_len == 2) + return; + + if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { + LIMIT_NETDEBUG(pr_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; + + dccp_encode_value_var(elapsed_time, to, elapsed_time_len); + + dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n", + debug_prefix, elapsed_time, + len, DCCP_SKB_CB(skb)->dccpd_seq); +} + +EXPORT_SYMBOL(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 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 = jiffies_to_usecs(jiffies - 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(pr_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, + ap->dccpap_ack_seqno, ap->dccpap_ack_ackno); +} + +static inline void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) +{ + const u32 now = htonl(tcp_time_stamp); + dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now)); +} + +static void dccp_insert_option_timestamp_echo(struct sock *sk, struct sk_buff *skb) +{ + struct dccp_sock *dp = dccp_sk(sk); +#ifdef 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 = jiffies_to_usecs(jiffies - dp->dccps_timestamp_time) / 10; + const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); + const int len = 6 + elapsed_time_len; + unsigned char *to; + + if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { + LIMIT_NETDEBUG(pr_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; + dccp_encode_value_var(elapsed_time, to, elapsed_time_len); + + dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n", + debug_prefix, dp->dccps_timestamp_echo, + len, DCCP_SKB_CB(skb)->dccpd_seq); + + dp->dccps_timestamp_echo = 0; + dp->dccps_timestamp_time = 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 && + dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno != DCCP_MAX_SEQNO + 1) + dccp_insert_option_ack_vector(sk, skb); + + dccp_insert_option_timestamp(sk, skb); + if (dp->dccps_timestamp_echo != 0) + dccp_insert_option_timestamp_echo(sk, skb); + } + + 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; + } + } +} + +struct dccp_ackpkts *dccp_ackpkts_alloc(unsigned int len, int priority) +{ + struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority); + + if (ap != NULL) { +#ifdef 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 = 0; + ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0; + } + + return ap; +} + +void dccp_ackpkts_free(struct dccp_ackpkts *ap) +{ + if (ap != NULL) { +#ifdef DCCP_DEBUG + memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len); +#endif + kfree(ap); + } +} + +static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap, + const unsigned int index) +{ + return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK; +} + +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 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) +{ + 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; + } + + ap->dccpap_buf_head = new_head; + + if (gap > 0) + memset(ap->dccpap_buf + ap->dccpap_buf_head + 1, + DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap); + + ap->dccpap_buf[ap->dccpap_buf_head] = state; + ap->dccpap_buf_vector_len += packets; + return 0; +} + +/* + * 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); + + /* + * 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); + /* + * valid packets not yet in dccpap_buf have a reserved entry, with + * a len equal to 0 + */ + if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED && + len == 0 && delta == 0) { /* Found our reserved seat! */ + dccp_pr_debug("Found %llu reserved seat!\n", ackno); + ap->dccpap_buf[index] = state; + goto out; + } + /* len == 0 means one packet */ + if (delta < len + 1) + goto out_duplicate; + + delta -= len + 1; + if (++index == ap->dccpap_buf_len) + index = 0; + } + } + + ap->dccpap_buf_ackno = ackno; + ap->dccpap_time = jiffies; +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", ackno); + return -EILSEQ; +} + +#ifdef 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, 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; + } + + printk("\n"); +} + +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 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, + ap->dccpap_ack_seqno, ap->dccpap_ack_ackno); + dccp_ackpkts_trow_away_ack_record(ap); + ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1; + } +} + +static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap, + struct sock *sk, u64 ackno, + const unsigned char len, + const unsigned char *vector) +{ + 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"); + + i = len; + while (i--) { + const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK); + u64 ackno_end_rl; + + dccp_set_seqno(&ackno_end_rl, ackno - rl); + + // 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 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, + ap->dccpap_ack_seqno, 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; + } +} |
