| /* |
| * net/dccp/ackvec.c |
| * |
| * An implementation of the DCCP protocol |
| * Copyright (c) 2005 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; version 2 of the License; |
| */ |
| |
| #include "ackvec.h" |
| #include "dccp.h" |
| |
| #include <linux/dccp.h> |
| #include <linux/init.h> |
| #include <linux/errno.h> |
| #include <linux/kernel.h> |
| #include <linux/skbuff.h> |
| #include <linux/slab.h> |
| |
| #include <net/sock.h> |
| |
| static kmem_cache_t *dccp_ackvec_slab; |
| static kmem_cache_t *dccp_ackvec_record_slab; |
| |
| static struct dccp_ackvec_record *dccp_ackvec_record_new(void) |
| { |
| struct dccp_ackvec_record *avr = |
| kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC); |
| |
| if (avr != NULL) |
| INIT_LIST_HEAD(&avr->dccpavr_node); |
| |
| return avr; |
| } |
| |
| static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr) |
| { |
| if (unlikely(avr == NULL)) |
| return; |
| /* Check if deleting a linked record */ |
| WARN_ON(!list_empty(&avr->dccpavr_node)); |
| kmem_cache_free(dccp_ackvec_record_slab, avr); |
| } |
| |
| static void dccp_ackvec_insert_avr(struct dccp_ackvec *av, |
| struct dccp_ackvec_record *avr) |
| { |
| /* |
| * AVRs are sorted by seqno. Since we are sending them in order, we |
| * just add the AVR at the head of the list. |
| * -sorbo. |
| */ |
| if (!list_empty(&av->dccpav_records)) { |
| const struct dccp_ackvec_record *head = |
| list_entry(av->dccpav_records.next, |
| struct dccp_ackvec_record, |
| dccpavr_node); |
| BUG_ON(before48(avr->dccpavr_ack_seqno, |
| head->dccpavr_ack_seqno)); |
| } |
| |
| list_add(&avr->dccpavr_node, &av->dccpav_records); |
| } |
| |
| int dccp_insert_option_ackvec(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: " : "server tx: "; |
| #endif |
| struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; |
| int len = av->dccpav_vec_len + 2; |
| struct timeval now; |
| u32 elapsed_time; |
| unsigned char *to, *from; |
| struct dccp_ackvec_record *avr; |
| |
| if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
| return -1; |
| |
| dccp_timestamp(sk, &now); |
| elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10; |
| |
| if (elapsed_time != 0 && |
| dccp_insert_option_elapsed_time(sk, skb, elapsed_time)) |
| return -1; |
| |
| avr = dccp_ackvec_record_new(); |
| if (avr == NULL) |
| return -1; |
| |
| DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
| |
| to = skb_push(skb, len); |
| *to++ = DCCPO_ACK_VECTOR_0; |
| *to++ = len; |
| |
| len = av->dccpav_vec_len; |
| from = av->dccpav_buf + av->dccpav_buf_head; |
| |
| /* Check if buf_head wraps */ |
| if ((int)av->dccpav_buf_head + len > DCCP_MAX_ACKVEC_LEN) { |
| const u32 tailsize = DCCP_MAX_ACKVEC_LEN - av->dccpav_buf_head; |
| |
| memcpy(to, from, tailsize); |
| to += tailsize; |
| len -= tailsize; |
| from = av->dccpav_buf; |
| } |
| |
| memcpy(to, from, len); |
| /* |
| * From RFC 4340, A.2: |
| * |
| * 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. |
| */ |
| avr->dccpavr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq; |
| avr->dccpavr_ack_ptr = av->dccpav_buf_head; |
| avr->dccpavr_ack_ackno = av->dccpav_buf_ackno; |
| avr->dccpavr_ack_nonce = av->dccpav_buf_nonce; |
| avr->dccpavr_sent_len = av->dccpav_vec_len; |
| |
| dccp_ackvec_insert_avr(av, avr); |
| |
| dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, " |
| "ack_ackno=%llu\n", |
| debug_prefix, avr->dccpavr_sent_len, |
| (unsigned long long)avr->dccpavr_ack_seqno, |
| (unsigned long long)avr->dccpavr_ack_ackno); |
| return 0; |
| } |
| |
| struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) |
| { |
| struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority); |
| |
| if (av != NULL) { |
| av->dccpav_buf_head = DCCP_MAX_ACKVEC_LEN - 1; |
| av->dccpav_buf_ackno = DCCP_MAX_SEQNO + 1; |
| av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0; |
| av->dccpav_ack_ptr = 0; |
| av->dccpav_time.tv_sec = 0; |
| av->dccpav_time.tv_usec = 0; |
| av->dccpav_vec_len = 0; |
| INIT_LIST_HEAD(&av->dccpav_records); |
| } |
| |
| return av; |
| } |
| |
| void dccp_ackvec_free(struct dccp_ackvec *av) |
| { |
| if (unlikely(av == NULL)) |
| return; |
| |
| if (!list_empty(&av->dccpav_records)) { |
| struct dccp_ackvec_record *avr, *next; |
| |
| list_for_each_entry_safe(avr, next, &av->dccpav_records, |
| dccpavr_node) { |
| list_del_init(&avr->dccpavr_node); |
| dccp_ackvec_record_delete(avr); |
| } |
| } |
| |
| kmem_cache_free(dccp_ackvec_slab, av); |
| } |
| |
| static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av, |
| const u8 index) |
| { |
| return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK; |
| } |
| |
| static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av, |
| const u8 index) |
| { |
| return av->dccpav_buf[index] & DCCP_ACKVEC_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_ackvec_set_buf_head_state(struct dccp_ackvec *av, |
| const unsigned int packets, |
| const unsigned char state) |
| { |
| unsigned int gap; |
| long new_head; |
| |
| if (av->dccpav_vec_len + packets > DCCP_MAX_ACKVEC_LEN) |
| return -ENOBUFS; |
| |
| gap = packets - 1; |
| new_head = av->dccpav_buf_head - packets; |
| |
| if (new_head < 0) { |
| if (gap > 0) { |
| memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED, |
| gap + new_head + 1); |
| gap = -new_head; |
| } |
| new_head += DCCP_MAX_ACKVEC_LEN; |
| } |
| |
| av->dccpav_buf_head = new_head; |
| |
| if (gap > 0) |
| memset(av->dccpav_buf + av->dccpav_buf_head + 1, |
| DCCP_ACKVEC_STATE_NOT_RECEIVED, gap); |
| |
| av->dccpav_buf[av->dccpav_buf_head] = state; |
| av->dccpav_vec_len += packets; |
| return 0; |
| } |
| |
| /* |
| * Implements the RFC 4340, Appendix A |
| */ |
| int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, |
| const u64 ackno, const 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 dccpav_buf. |
| * |
| * We may well decide to do buffer compression, etc, but for now lets |
| * just drop. |
| * |
| * From Appendix A.1.1 (`New Packets'): |
| * |
| * 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 (av->dccpav_vec_len == 0) { |
| av->dccpav_buf[av->dccpav_buf_head] = state; |
| av->dccpav_vec_len = 1; |
| } else if (after48(ackno, av->dccpav_buf_ackno)) { |
| const u64 delta = dccp_delta_seqno(av->dccpav_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_ackvec_state(av, av->dccpav_buf_head) == state && |
| (dccp_ackvec_len(av, av->dccpav_buf_head) < |
| DCCP_ACKVEC_LEN_MASK)) |
| av->dccpav_buf[av->dccpav_buf_head]++; |
| else if (dccp_ackvec_set_buf_head_state(av, delta, state)) |
| return -ENOBUFS; |
| } else { |
| /* |
| * A.1.2. Old Packets |
| * |
| * When a packet with Sequence Number S <= buf_ackno |
| * arrives, 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, av->dccpav_buf_ackno); |
| u8 index = av->dccpav_buf_head; |
| |
| while (1) { |
| const u8 len = dccp_ackvec_len(av, index); |
| const u8 state = dccp_ackvec_state(av, index); |
| /* |
| * valid packets not yet in dccpav_buf have a reserved |
| * entry, with a len equal to 0. |
| */ |
| if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED && |
| len == 0 && delta == 0) { /* Found our |
| reserved seat! */ |
| dccp_pr_debug("Found %llu reserved seat!\n", |
| (unsigned long long)ackno); |
| av->dccpav_buf[index] = state; |
| goto out; |
| } |
| /* len == 0 means one packet */ |
| if (delta < len + 1) |
| goto out_duplicate; |
| |
| delta -= len + 1; |
| if (++index == DCCP_MAX_ACKVEC_LEN) |
| index = 0; |
| } |
| } |
| |
| av->dccpav_buf_ackno = ackno; |
| dccp_timestamp(sk, &av->dccpav_time); |
| out: |
| return 0; |
| |
| out_duplicate: |
| /* Duplicate packet */ |
| dccp_pr_debug("Received a dup or already considered lost " |
| "packet: %llu\n", (unsigned long long)ackno); |
| return -EILSEQ; |
| } |
| |
| #ifdef CONFIG_IP_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, |
| (unsigned long long)ackno); |
| |
| while (len--) { |
| const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6; |
| const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; |
| |
| printk("%d,%d|", state, rl); |
| ++vector; |
| } |
| |
| printk("\n"); |
| } |
| |
| void dccp_ackvec_print(const struct dccp_ackvec *av) |
| { |
| dccp_ackvector_print(av->dccpav_buf_ackno, |
| av->dccpav_buf + av->dccpav_buf_head, |
| av->dccpav_vec_len); |
| } |
| #endif |
| |
| static void dccp_ackvec_throw_record(struct dccp_ackvec *av, |
| struct dccp_ackvec_record *avr) |
| { |
| struct dccp_ackvec_record *next; |
| |
| /* sort out vector length */ |
| if (av->dccpav_buf_head <= avr->dccpavr_ack_ptr) |
| av->dccpav_vec_len = avr->dccpavr_ack_ptr - av->dccpav_buf_head; |
| else |
| av->dccpav_vec_len = DCCP_MAX_ACKVEC_LEN - 1 |
| - av->dccpav_buf_head |
| + avr->dccpavr_ack_ptr; |
| |
| /* free records */ |
| list_for_each_entry_safe_from(avr, next, &av->dccpav_records, |
| dccpavr_node) { |
| list_del_init(&avr->dccpavr_node); |
| dccp_ackvec_record_delete(avr); |
| } |
| } |
| |
| void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk, |
| const u64 ackno) |
| { |
| struct dccp_ackvec_record *avr; |
| |
| /* |
| * If we traverse backwards, it should be faster when we have large |
| * windows. We will be receiving ACKs for stuff we sent a while back |
| * -sorbo. |
| */ |
| list_for_each_entry_reverse(avr, &av->dccpav_records, dccpavr_node) { |
| if (ackno == avr->dccpavr_ack_seqno) { |
| #ifdef CONFIG_IP_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, |
| (unsigned long long)avr->dccpavr_ack_seqno, |
| (unsigned long long)avr->dccpavr_ack_ackno); |
| dccp_ackvec_throw_record(av, avr); |
| break; |
| } |
| } |
| } |
| |
| static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av, |
| struct sock *sk, u64 ackno, |
| const unsigned char len, |
| const unsigned char *vector) |
| { |
| unsigned char i; |
| struct dccp_ackvec_record *avr; |
| |
| /* Check if we actually sent an ACK vector */ |
| if (list_empty(&av->dccpav_records)) |
| return; |
| |
| i = len; |
| /* |
| * XXX |
| * I think it might be more efficient to work backwards. See comment on |
| * rcv_ackno. -sorbo. |
| */ |
| avr = list_entry(av->dccpav_records.next, struct dccp_ackvec_record, |
| dccpavr_node); |
| while (i--) { |
| const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; |
| u64 ackno_end_rl; |
| |
| dccp_set_seqno(&ackno_end_rl, ackno - rl); |
| |
| /* |
| * If our AVR sequence number is greater than the ack, go |
| * forward in the AVR list until it is not so. |
| */ |
| list_for_each_entry_from(avr, &av->dccpav_records, |
| dccpavr_node) { |
| if (!after48(avr->dccpavr_ack_seqno, ackno)) |
| goto found; |
| } |
| /* End of the dccpav_records list, not found, exit */ |
| break; |
| found: |
| if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, ackno)) { |
| const u8 state = *vector & DCCP_ACKVEC_STATE_MASK; |
| if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) { |
| #ifdef CONFIG_IP_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, |
| (unsigned long long) |
| avr->dccpavr_ack_seqno, |
| (unsigned long long) |
| avr->dccpavr_ack_ackno); |
| dccp_ackvec_throw_record(av, avr); |
| break; |
| } |
| /* |
| * If it wasn't received, continue scanning... we might |
| * find another one. |
| */ |
| } |
| |
| dccp_set_seqno(&ackno, ackno_end_rl - 1); |
| ++vector; |
| } |
| } |
| |
| int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, |
| const u8 opt, const u8 *value, const u8 len) |
| { |
| if (len > DCCP_MAX_ACKVEC_LEN) |
| return -1; |
| |
| /* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */ |
| dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk, |
| DCCP_SKB_CB(skb)->dccpd_ack_seq, |
| len, value); |
| return 0; |
| } |
| |
| static char dccp_ackvec_slab_msg[] __initdata = |
| KERN_CRIT "DCCP: Unable to create ack vectors slab caches\n"; |
| |
| int __init dccp_ackvec_init(void) |
| { |
| dccp_ackvec_slab = kmem_cache_create("dccp_ackvec", |
| sizeof(struct dccp_ackvec), 0, |
| SLAB_HWCACHE_ALIGN, NULL, NULL); |
| if (dccp_ackvec_slab == NULL) |
| goto out_err; |
| |
| dccp_ackvec_record_slab = |
| kmem_cache_create("dccp_ackvec_record", |
| sizeof(struct dccp_ackvec_record), |
| 0, SLAB_HWCACHE_ALIGN, NULL, NULL); |
| if (dccp_ackvec_record_slab == NULL) |
| goto out_destroy_slab; |
| |
| return 0; |
| |
| out_destroy_slab: |
| kmem_cache_destroy(dccp_ackvec_slab); |
| dccp_ackvec_slab = NULL; |
| out_err: |
| printk(dccp_ackvec_slab_msg); |
| return -ENOBUFS; |
| } |
| |
| void dccp_ackvec_exit(void) |
| { |
| if (dccp_ackvec_slab != NULL) { |
| kmem_cache_destroy(dccp_ackvec_slab); |
| dccp_ackvec_slab = NULL; |
| } |
| if (dccp_ackvec_record_slab != NULL) { |
| kmem_cache_destroy(dccp_ackvec_record_slab); |
| dccp_ackvec_record_slab = NULL; |
| } |
| } |