diff options
Diffstat (limited to 'net/dccp/minisocks.c')
| -rw-r--r-- | net/dccp/minisocks.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c new file mode 100644 index 000000000..91e7a2202 --- /dev/null +++ b/net/dccp/minisocks.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * net/dccp/minisocks.c + * + * An implementation of the DCCP protocol + * Arnaldo Carvalho de Melo <acme@conectiva.com.br> + */ + +#include <linux/dccp.h> +#include <linux/gfp.h> +#include <linux/kernel.h> +#include <linux/skbuff.h> +#include <linux/timer.h> + +#include <net/sock.h> +#include <net/xfrm.h> +#include <net/inet_timewait_sock.h> + +#include "ackvec.h" +#include "ccid.h" +#include "dccp.h" +#include "feat.h" + +struct inet_timewait_death_row dccp_death_row = { + .sysctl_max_tw_buckets = NR_FILE * 2, + .hashinfo = &dccp_hashinfo, +}; + +EXPORT_SYMBOL_GPL(dccp_death_row); + +void dccp_time_wait(struct sock *sk, int state, int timeo) +{ + struct inet_timewait_sock *tw; + + tw = inet_twsk_alloc(sk, &dccp_death_row, state); + + if (tw != NULL) { + const struct inet_connection_sock *icsk = inet_csk(sk); + const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); +#if IS_ENABLED(CONFIG_IPV6) + if (tw->tw_family == PF_INET6) { + tw->tw_v6_daddr = sk->sk_v6_daddr; + tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr; + tw->tw_ipv6only = sk->sk_ipv6only; + } +#endif + + /* Get the TIME_WAIT timeout firing. */ + if (timeo < rto) + timeo = rto; + + if (state == DCCP_TIME_WAIT) + timeo = DCCP_TIMEWAIT_LEN; + + /* tw_timer is pinned, so we need to make sure BH are disabled + * in following section, otherwise timer handler could run before + * we complete the initialization. + */ + local_bh_disable(); + inet_twsk_schedule(tw, timeo); + /* Linkage updates. + * Note that access to tw after this point is illegal. + */ + inet_twsk_hashdance(tw, sk, &dccp_hashinfo); + local_bh_enable(); + } else { + /* Sorry, if we're out of memory, just CLOSE this + * socket up. We've got bigger problems than + * non-graceful socket closings. + */ + DCCP_WARN("time wait bucket table overflow\n"); + } + + dccp_done(sk); +} + +struct sock *dccp_create_openreq_child(const struct sock *sk, + const struct request_sock *req, + const struct sk_buff *skb) +{ + /* + * Step 3: Process LISTEN state + * + * (* Generate a new socket and switch to that socket *) + * Set S := new socket for this port pair + */ + struct sock *newsk = inet_csk_clone_lock(sk, req, GFP_ATOMIC); + + if (newsk != NULL) { + struct dccp_request_sock *dreq = dccp_rsk(req); + struct inet_connection_sock *newicsk = inet_csk(newsk); + struct dccp_sock *newdp = dccp_sk(newsk); + + newdp->dccps_role = DCCP_ROLE_SERVER; + newdp->dccps_hc_rx_ackvec = NULL; + newdp->dccps_service_list = NULL; + newdp->dccps_hc_rx_ccid = NULL; + newdp->dccps_hc_tx_ccid = NULL; + newdp->dccps_service = dreq->dreq_service; + newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo; + newdp->dccps_timestamp_time = dreq->dreq_timestamp_time; + newicsk->icsk_rto = DCCP_TIMEOUT_INIT; + + INIT_LIST_HEAD(&newdp->dccps_featneg); + /* + * Step 3: Process LISTEN state + * + * Choose S.ISS (initial seqno) or set from Init Cookies + * Initialize S.GAR := S.ISS + * Set S.ISR, S.GSR from packet (or Init Cookies) + * + * Setting AWL/AWH and SWL/SWH happens as part of the feature + * activation below, as these windows all depend on the local + * and remote Sequence Window feature values (7.5.2). + */ + newdp->dccps_iss = dreq->dreq_iss; + newdp->dccps_gss = dreq->dreq_gss; + newdp->dccps_gar = newdp->dccps_iss; + newdp->dccps_isr = dreq->dreq_isr; + newdp->dccps_gsr = dreq->dreq_gsr; + + /* + * Activate features: initialise CCIDs, sequence windows etc. + */ + if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) { + sk_free_unlock_clone(newsk); + return NULL; + } + dccp_init_xmit_timers(newsk); + + __DCCP_INC_STATS(DCCP_MIB_PASSIVEOPENS); + } + return newsk; +} + +EXPORT_SYMBOL_GPL(dccp_create_openreq_child); + +/* + * Process an incoming packet for RESPOND sockets represented + * as an request_sock. + */ +struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, + struct request_sock *req) +{ + struct sock *child = NULL; + struct dccp_request_sock *dreq = dccp_rsk(req); + bool own_req; + + /* TCP/DCCP listeners became lockless. + * DCCP stores complex state in its request_sock, so we need + * a protection for them, now this code runs without being protected + * by the parent (listener) lock. + */ + spin_lock_bh(&dreq->dreq_lock); + + /* Check for retransmitted REQUEST */ + if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { + + if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) { + dccp_pr_debug("Retransmitted REQUEST\n"); + dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq; + /* + * Send another RESPONSE packet + * To protect against Request floods, increment retrans + * counter (backoff, monitored by dccp_response_timer). + */ + inet_rtx_syn_ack(sk, req); + } + /* Network Duplicate, discard packet */ + goto out; + } + + DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; + + if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && + dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) + goto drop; + + /* Invalid ACK */ + if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, + dreq->dreq_iss, dreq->dreq_gss)) { + dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " + "dreq_iss=%llu, dreq_gss=%llu\n", + (unsigned long long) + DCCP_SKB_CB(skb)->dccpd_ack_seq, + (unsigned long long) dreq->dreq_iss, + (unsigned long long) dreq->dreq_gss); + goto drop; + } + + if (dccp_parse_options(sk, dreq, skb)) + goto drop; + + child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL, + req, &own_req); + if (child) { + child = inet_csk_complete_hashdance(sk, child, req, own_req); + goto out; + } + + DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; +drop: + if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) + req->rsk_ops->send_reset(sk, skb); + + inet_csk_reqsk_queue_drop(sk, req); +out: + spin_unlock_bh(&dreq->dreq_lock); + return child; +} + +EXPORT_SYMBOL_GPL(dccp_check_req); + +/* + * Queue segment on the new socket if the new socket is active, + * otherwise we just shortcircuit this and continue with + * the new socket. + */ +int dccp_child_process(struct sock *parent, struct sock *child, + struct sk_buff *skb) + __releases(child) +{ + int ret = 0; + const int state = child->sk_state; + + if (!sock_owned_by_user(child)) { + ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), + skb->len); + + /* Wakeup parent, send SIGIO */ + if (state == DCCP_RESPOND && child->sk_state != state) + parent->sk_data_ready(parent); + } else { + /* Alas, it is possible again, because we do lookup + * in main socket hash table and lock on listening + * socket does not protect us more. + */ + __sk_add_backlog(child, skb); + } + + bh_unlock_sock(child); + sock_put(child); + return ret; +} + +EXPORT_SYMBOL_GPL(dccp_child_process); + +void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, + struct request_sock *rsk) +{ + DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state"); +} + +EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); + +int dccp_reqsk_init(struct request_sock *req, + struct dccp_sock const *dp, struct sk_buff const *skb) +{ + struct dccp_request_sock *dreq = dccp_rsk(req); + + spin_lock_init(&dreq->dreq_lock); + inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport; + inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport); + inet_rsk(req)->acked = 0; + dreq->dreq_timestamp_echo = 0; + + /* inherit feature negotiation options from listening socket */ + return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg); +} + +EXPORT_SYMBOL_GPL(dccp_reqsk_init); |