v4.19.13 snapshot.
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
new file mode 100644
index 0000000..ab9242e
--- /dev/null
+++ b/include/net/sctp/sctp.h
@@ -0,0 +1,623 @@
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2003 Intel Corp.
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * The base lksctp header.
+ *
+ * This SCTP implementation 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, or (at your option)
+ * any later version.
+ *
+ * This SCTP implementation is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * ************************
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU CC; see the file COPYING. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ * lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ * La Monte H.P. Yarroll <piggy@acm.org>
+ * Xingang Guo <xingang.guo@intel.com>
+ * Jon Grimm <jgrimm@us.ibm.com>
+ * Daisy Chang <daisyc@us.ibm.com>
+ * Sridhar Samudrala <sri@us.ibm.com>
+ * Ardelle Fan <ardelle.fan@intel.com>
+ * Ryan Layer <rmlayer@us.ibm.com>
+ * Kevin Gao <kevin.gao@intel.com>
+ */
+
+#ifndef __net_sctp_h__
+#define __net_sctp_h__
+
+/* Header Strategy.
+ * Start getting some control over the header file depencies:
+ * includes
+ * constants
+ * structs
+ * prototypes
+ * macros, externs, and inlines
+ *
+ * Move test_frame specific items out of the kernel headers
+ * and into the test frame headers. This is not perfect in any sense
+ * and will continue to evolve.
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/in.h>
+#include <linux/tty.h>
+#include <linux/proc_fs.h>
+#include <linux/spinlock.h>
+#include <linux/jiffies.h>
+#include <linux/idr.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+#include <net/ip6_route.h>
+#endif
+
+#include <linux/uaccess.h>
+#include <asm/page.h>
+#include <net/sock.h>
+#include <net/snmp.h>
+#include <net/sctp/structs.h>
+#include <net/sctp/constants.h>
+
+#ifdef CONFIG_IP_SCTP_MODULE
+#define SCTP_PROTOSW_FLAG 0
+#else /* static! */
+#define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
+#endif
+
+/* Round an int up to the next multiple of 4. */
+#define SCTP_PAD4(s) (((s)+3)&~3)
+/* Truncate to the previous multiple of 4. */
+#define SCTP_TRUNC4(s) ((s)&~3)
+
+/*
+ * Function declarations.
+ */
+
+/*
+ * sctp/protocol.c
+ */
+int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *addr,
+ enum sctp_scope, gfp_t gfp, int flags);
+struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
+int sctp_register_pf(struct sctp_pf *, sa_family_t);
+void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
+
+/*
+ * sctp/socket.c
+ */
+int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
+ int addr_len, int flags);
+int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
+int sctp_inet_listen(struct socket *sock, int backlog);
+void sctp_write_space(struct sock *sk);
+void sctp_data_ready(struct sock *sk);
+__poll_t sctp_poll(struct file *file, struct socket *sock,
+ poll_table *wait);
+void sctp_sock_rfree(struct sk_buff *skb);
+void sctp_copy_sock(struct sock *newsk, struct sock *sk,
+ struct sctp_association *asoc);
+extern struct percpu_counter sctp_sockets_allocated;
+int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
+struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
+
+void sctp_transport_walk_start(struct rhashtable_iter *iter);
+void sctp_transport_walk_stop(struct rhashtable_iter *iter);
+struct sctp_transport *sctp_transport_get_next(struct net *net,
+ struct rhashtable_iter *iter);
+struct sctp_transport *sctp_transport_get_idx(struct net *net,
+ struct rhashtable_iter *iter, int pos);
+int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
+ struct net *net,
+ const union sctp_addr *laddr,
+ const union sctp_addr *paddr, void *p);
+int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
+ int (*cb_done)(struct sctp_transport *, void *),
+ struct net *net, int *pos, void *p);
+int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
+int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
+ struct sctp_info *info);
+
+/*
+ * sctp/primitive.c
+ */
+int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
+int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
+int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
+int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
+int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
+int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
+int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
+ void *arg);
+
+/*
+ * sctp/input.c
+ */
+int sctp_rcv(struct sk_buff *skb);
+void sctp_v4_err(struct sk_buff *skb, u32 info);
+void sctp_hash_endpoint(struct sctp_endpoint *);
+void sctp_unhash_endpoint(struct sctp_endpoint *);
+struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
+ struct sctphdr *, struct sctp_association **,
+ struct sctp_transport **);
+void sctp_err_finish(struct sock *, struct sctp_transport *);
+void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
+ struct sctp_transport *t, __u32 pmtu);
+void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
+ struct sk_buff *);
+void sctp_icmp_proto_unreachable(struct sock *sk,
+ struct sctp_association *asoc,
+ struct sctp_transport *t);
+void sctp_backlog_migrate(struct sctp_association *assoc,
+ struct sock *oldsk, struct sock *newsk);
+int sctp_transport_hashtable_init(void);
+void sctp_transport_hashtable_destroy(void);
+int sctp_hash_transport(struct sctp_transport *t);
+void sctp_unhash_transport(struct sctp_transport *t);
+struct sctp_transport *sctp_addrs_lookup_transport(
+ struct net *net,
+ const union sctp_addr *laddr,
+ const union sctp_addr *paddr);
+struct sctp_transport *sctp_epaddr_lookup_transport(
+ const struct sctp_endpoint *ep,
+ const union sctp_addr *paddr);
+
+/*
+ * sctp/proc.c
+ */
+int __net_init sctp_proc_init(struct net *net);
+
+/*
+ * sctp/offload.c
+ */
+int sctp_offload_init(void);
+
+/*
+ * sctp/stream_sched.c
+ */
+void sctp_sched_ops_init(void);
+
+/*
+ * sctp/stream.c
+ */
+int sctp_send_reset_streams(struct sctp_association *asoc,
+ struct sctp_reset_streams *params);
+int sctp_send_reset_assoc(struct sctp_association *asoc);
+int sctp_send_add_streams(struct sctp_association *asoc,
+ struct sctp_add_streams *params);
+
+/*
+ * Module global variables
+ */
+
+ /*
+ * sctp/protocol.c
+ */
+extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
+extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
+extern long sysctl_sctp_mem[3];
+extern int sysctl_sctp_rmem[3];
+extern int sysctl_sctp_wmem[3];
+
+/*
+ * Section: Macros, externs, and inlines
+ */
+
+/* SCTP SNMP MIB stats handlers */
+#define SCTP_INC_STATS(net, field) SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
+#define __SCTP_INC_STATS(net, field) __SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
+#define SCTP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
+
+/* sctp mib definitions */
+enum {
+ SCTP_MIB_NUM = 0,
+ SCTP_MIB_CURRESTAB, /* CurrEstab */
+ SCTP_MIB_ACTIVEESTABS, /* ActiveEstabs */
+ SCTP_MIB_PASSIVEESTABS, /* PassiveEstabs */
+ SCTP_MIB_ABORTEDS, /* Aborteds */
+ SCTP_MIB_SHUTDOWNS, /* Shutdowns */
+ SCTP_MIB_OUTOFBLUES, /* OutOfBlues */
+ SCTP_MIB_CHECKSUMERRORS, /* ChecksumErrors */
+ SCTP_MIB_OUTCTRLCHUNKS, /* OutCtrlChunks */
+ SCTP_MIB_OUTORDERCHUNKS, /* OutOrderChunks */
+ SCTP_MIB_OUTUNORDERCHUNKS, /* OutUnorderChunks */
+ SCTP_MIB_INCTRLCHUNKS, /* InCtrlChunks */
+ SCTP_MIB_INORDERCHUNKS, /* InOrderChunks */
+ SCTP_MIB_INUNORDERCHUNKS, /* InUnorderChunks */
+ SCTP_MIB_FRAGUSRMSGS, /* FragUsrMsgs */
+ SCTP_MIB_REASMUSRMSGS, /* ReasmUsrMsgs */
+ SCTP_MIB_OUTSCTPPACKS, /* OutSCTPPacks */
+ SCTP_MIB_INSCTPPACKS, /* InSCTPPacks */
+ SCTP_MIB_T1_INIT_EXPIREDS,
+ SCTP_MIB_T1_COOKIE_EXPIREDS,
+ SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
+ SCTP_MIB_T3_RTX_EXPIREDS,
+ SCTP_MIB_T4_RTO_EXPIREDS,
+ SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
+ SCTP_MIB_DELAY_SACK_EXPIREDS,
+ SCTP_MIB_AUTOCLOSE_EXPIREDS,
+ SCTP_MIB_T1_RETRANSMITS,
+ SCTP_MIB_T3_RETRANSMITS,
+ SCTP_MIB_PMTUD_RETRANSMITS,
+ SCTP_MIB_FAST_RETRANSMITS,
+ SCTP_MIB_IN_PKT_SOFTIRQ,
+ SCTP_MIB_IN_PKT_BACKLOG,
+ SCTP_MIB_IN_PKT_DISCARDS,
+ SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
+ __SCTP_MIB_MAX
+};
+
+#define SCTP_MIB_MAX __SCTP_MIB_MAX
+struct sctp_mib {
+ unsigned long mibs[SCTP_MIB_MAX];
+};
+
+/* helper function to track stats about max rto and related transport */
+static inline void sctp_max_rto(struct sctp_association *asoc,
+ struct sctp_transport *trans)
+{
+ if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
+ asoc->stats.max_obs_rto = trans->rto;
+ memset(&asoc->stats.obs_rto_ipaddr, 0,
+ sizeof(struct sockaddr_storage));
+ memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
+ trans->af_specific->sockaddr_len);
+ }
+}
+
+/*
+ * Macros for keeping a global reference of object allocations.
+ */
+#ifdef CONFIG_SCTP_DBG_OBJCNT
+
+extern atomic_t sctp_dbg_objcnt_sock;
+extern atomic_t sctp_dbg_objcnt_ep;
+extern atomic_t sctp_dbg_objcnt_assoc;
+extern atomic_t sctp_dbg_objcnt_transport;
+extern atomic_t sctp_dbg_objcnt_chunk;
+extern atomic_t sctp_dbg_objcnt_bind_addr;
+extern atomic_t sctp_dbg_objcnt_bind_bucket;
+extern atomic_t sctp_dbg_objcnt_addr;
+extern atomic_t sctp_dbg_objcnt_datamsg;
+extern atomic_t sctp_dbg_objcnt_keys;
+
+/* Macros to atomically increment/decrement objcnt counters. */
+#define SCTP_DBG_OBJCNT_INC(name) \
+atomic_inc(&sctp_dbg_objcnt_## name)
+#define SCTP_DBG_OBJCNT_DEC(name) \
+atomic_dec(&sctp_dbg_objcnt_## name)
+#define SCTP_DBG_OBJCNT(name) \
+atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
+
+/* Macro to help create new entries in in the global array of
+ * objcnt counters.
+ */
+#define SCTP_DBG_OBJCNT_ENTRY(name) \
+{.label= #name, .counter= &sctp_dbg_objcnt_## name}
+
+void sctp_dbg_objcnt_init(struct net *);
+
+#else
+
+#define SCTP_DBG_OBJCNT_INC(name)
+#define SCTP_DBG_OBJCNT_DEC(name)
+
+static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
+
+#endif /* CONFIG_SCTP_DBG_OBJCOUNT */
+
+#if defined CONFIG_SYSCTL
+void sctp_sysctl_register(void);
+void sctp_sysctl_unregister(void);
+int sctp_sysctl_net_register(struct net *net);
+void sctp_sysctl_net_unregister(struct net *net);
+#else
+static inline void sctp_sysctl_register(void) { return; }
+static inline void sctp_sysctl_unregister(void) { return; }
+static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
+static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
+#endif
+
+/* Size of Supported Address Parameter for 'x' address types. */
+#define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
+
+#if IS_ENABLED(CONFIG_IPV6)
+
+void sctp_v6_pf_init(void);
+void sctp_v6_pf_exit(void);
+int sctp_v6_protosw_init(void);
+void sctp_v6_protosw_exit(void);
+int sctp_v6_add_protocol(void);
+void sctp_v6_del_protocol(void);
+
+#else /* #ifdef defined(CONFIG_IPV6) */
+
+static inline void sctp_v6_pf_init(void) { return; }
+static inline void sctp_v6_pf_exit(void) { return; }
+static inline int sctp_v6_protosw_init(void) { return 0; }
+static inline void sctp_v6_protosw_exit(void) { return; }
+static inline int sctp_v6_add_protocol(void) { return 0; }
+static inline void sctp_v6_del_protocol(void) { return; }
+
+#endif /* #if defined(CONFIG_IPV6) */
+
+
+/* Map an association to an assoc_id. */
+static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
+{
+ return asoc ? asoc->assoc_id : 0;
+}
+
+static inline enum sctp_sstat_state
+sctp_assoc_to_state(const struct sctp_association *asoc)
+{
+ /* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
+ * got rid of it in kernel space. Therefore SCTP_CLOSED et al
+ * start at =1 in user space, but actually as =0 in kernel space.
+ * Now that we can not break user space and SCTP_EMPTY is exposed
+ * there, we need to fix it up with an ugly offset not to break
+ * applications. :(
+ */
+ return asoc->state + 1;
+}
+
+/* Look up the association by its id. */
+struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
+
+int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
+
+/* A macro to walk a list of skbs. */
+#define sctp_skb_for_each(pos, head, tmp) \
+ skb_queue_walk_safe(head, pos, tmp)
+
+/**
+ * sctp_list_dequeue - remove from the head of the queue
+ * @list: list to dequeue from
+ *
+ * Remove the head of the list. The head item is
+ * returned or %NULL if the list is empty.
+ */
+
+static inline struct list_head *sctp_list_dequeue(struct list_head *list)
+{
+ struct list_head *result = NULL;
+
+ if (!list_empty(list)) {
+ result = list->next;
+ list_del_init(result);
+ }
+ return result;
+}
+
+/* SCTP version of skb_set_owner_r. We need this one because
+ * of the way we have to do receive buffer accounting on bundled
+ * chunks.
+ */
+static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
+{
+ struct sctp_ulpevent *event = sctp_skb2event(skb);
+
+ skb_orphan(skb);
+ skb->sk = sk;
+ skb->destructor = sctp_sock_rfree;
+ atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
+ /*
+ * This mimics the behavior of skb_set_owner_r
+ */
+ sk->sk_forward_alloc -= event->rmem_len;
+}
+
+/* Tests if the list has one and only one entry. */
+static inline int sctp_list_single_entry(struct list_head *head)
+{
+ return (head->next != head) && (head->next == head->prev);
+}
+
+static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
+{
+ return !list_empty(&chunk->list);
+}
+
+/* Walk through a list of TLV parameters. Don't trust the
+ * individual parameter lengths and instead depend on
+ * the chunk length to indicate when to stop. Make sure
+ * there is room for a param header too.
+ */
+#define sctp_walk_params(pos, chunk, member)\
+_sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
+
+#define _sctp_walk_params(pos, chunk, end, member)\
+for (pos.v = chunk->member;\
+ (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
+ (void *)chunk + end) &&\
+ pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
+ ntohs(pos.p->length) >= sizeof(struct sctp_paramhdr);\
+ pos.v += SCTP_PAD4(ntohs(pos.p->length)))
+
+#define sctp_walk_errors(err, chunk_hdr)\
+_sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
+
+#define _sctp_walk_errors(err, chunk_hdr, end)\
+for (err = (struct sctp_errhdr *)((void *)chunk_hdr + \
+ sizeof(struct sctp_chunkhdr));\
+ ((void *)err + offsetof(struct sctp_errhdr, length) + sizeof(err->length) <=\
+ (void *)chunk_hdr + end) &&\
+ (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
+ ntohs(err->length) >= sizeof(struct sctp_errhdr); \
+ err = (struct sctp_errhdr *)((void *)err + SCTP_PAD4(ntohs(err->length))))
+
+#define sctp_walk_fwdtsn(pos, chunk)\
+_sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
+
+#define _sctp_walk_fwdtsn(pos, chunk, end)\
+for (pos = chunk->subh.fwdtsn_hdr->skip;\
+ (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
+ pos++)
+
+/* External references. */
+
+extern struct proto sctp_prot;
+extern struct proto sctpv6_prot;
+void sctp_put_port(struct sock *sk);
+
+extern struct idr sctp_assocs_id;
+extern spinlock_t sctp_assocs_id_lock;
+
+/* Static inline functions. */
+
+/* Convert from an IP version number to an Address Family symbol. */
+static inline int ipver2af(__u8 ipver)
+{
+ switch (ipver) {
+ case 4:
+ return AF_INET;
+ case 6:
+ return AF_INET6;
+ default:
+ return 0;
+ }
+}
+
+/* Convert from an address parameter type to an address family. */
+static inline int param_type2af(__be16 type)
+{
+ switch (type) {
+ case SCTP_PARAM_IPV4_ADDRESS:
+ return AF_INET;
+ case SCTP_PARAM_IPV6_ADDRESS:
+ return AF_INET6;
+ default:
+ return 0;
+ }
+}
+
+/* Warning: The following hash functions assume a power of two 'size'. */
+/* This is the hash function for the SCTP port hash table. */
+static inline int sctp_phashfn(struct net *net, __u16 lport)
+{
+ return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
+}
+
+/* This is the hash function for the endpoint hash table. */
+static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
+{
+ return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
+}
+
+#define sctp_for_each_hentry(epb, head) \
+ hlist_for_each_entry(epb, head, node)
+
+/* Is a socket of this style? */
+#define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
+static inline int __sctp_style(const struct sock *sk,
+ enum sctp_socket_type style)
+{
+ return sctp_sk(sk)->type == style;
+}
+
+/* Is the association in this state? */
+#define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
+static inline int __sctp_state(const struct sctp_association *asoc,
+ enum sctp_state state)
+{
+ return asoc->state == state;
+}
+
+/* Is the socket in this state? */
+#define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
+static inline int __sctp_sstate(const struct sock *sk,
+ enum sctp_sock_state state)
+{
+ return sk->sk_state == state;
+}
+
+/* Map v4-mapped v6 address back to v4 address */
+static inline void sctp_v6_map_v4(union sctp_addr *addr)
+{
+ addr->v4.sin_family = AF_INET;
+ addr->v4.sin_port = addr->v6.sin6_port;
+ addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
+}
+
+/* Map v4 address to v4-mapped v6 address */
+static inline void sctp_v4_map_v6(union sctp_addr *addr)
+{
+ __be16 port;
+
+ port = addr->v4.sin_port;
+ addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
+ addr->v6.sin6_port = port;
+ addr->v6.sin6_family = AF_INET6;
+ addr->v6.sin6_flowinfo = 0;
+ addr->v6.sin6_scope_id = 0;
+ addr->v6.sin6_addr.s6_addr32[0] = 0;
+ addr->v6.sin6_addr.s6_addr32[1] = 0;
+ addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
+}
+
+/* The cookie is always 0 since this is how it's used in the
+ * pmtu code.
+ */
+static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
+{
+ if (t->dst && !dst_check(t->dst, t->dst_cookie))
+ sctp_transport_dst_release(t);
+
+ return t->dst;
+}
+
+/* Calculate max payload size given a MTU, or the total overhead if
+ * given MTU is zero
+ */
+static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
+ __u32 mtu, __u32 extra)
+{
+ __u32 overhead = sizeof(struct sctphdr) + extra;
+
+ if (sp)
+ overhead += sp->pf->af->net_header_len;
+ else
+ overhead += sizeof(struct ipv6hdr);
+
+ if (WARN_ON_ONCE(mtu && mtu <= overhead))
+ mtu = overhead;
+
+ return mtu ? mtu - overhead : overhead;
+}
+
+static inline __u32 sctp_dst_mtu(const struct dst_entry *dst)
+{
+ return SCTP_TRUNC4(max_t(__u32, dst_mtu(dst),
+ SCTP_DEFAULT_MINSEGMENT));
+}
+
+static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
+{
+ __u32 pmtu = sctp_dst_mtu(t->dst);
+
+ if (t->pathmtu == pmtu)
+ return true;
+
+ t->pathmtu = pmtu;
+
+ return false;
+}
+
+#endif /* __net_sctp_h__ */