1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/ip.h>
4 #include <linux/sctp.h>
5 #include <net/ip.h>
6 #include <net/ip6_checksum.h>
7 #include <linux/netfilter.h>
8 #include <linux/netfilter_ipv4.h>
9 #include <net/sctp/checksum.h>
10 #include <net/ip_vs.h>
11 
12 static int
13 sctp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp);
14 
15 static int
16 sctp_conn_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb,
17 		   struct ip_vs_proto_data *pd,
18 		   int *verdict, struct ip_vs_conn **cpp,
19 		   struct ip_vs_iphdr *iph)
20 {
21 	struct ip_vs_service *svc;
22 	struct sctp_chunkhdr _schunkh, *sch;
23 	struct sctphdr *sh, _sctph;
24 	__be16 _ports[2], *ports = NULL;
25 
26 	if (likely(!ip_vs_iph_icmp(iph))) {
27 		sh = skb_header_pointer(skb, iph->len, sizeof(_sctph), &_sctph);
28 		if (sh) {
29 			sch = skb_header_pointer(skb, iph->len + sizeof(_sctph),
30 						 sizeof(_schunkh), &_schunkh);
31 			if (sch) {
32 				if (sch->type == SCTP_CID_ABORT ||
33 				    !(sysctl_sloppy_sctp(ipvs) ||
34 				      sch->type == SCTP_CID_INIT))
35 					return 1;
36 				ports = &sh->source;
37 			}
38 		}
39 	} else {
40 		ports = skb_header_pointer(
41 			skb, iph->len, sizeof(_ports), &_ports);
42 	}
43 
44 	if (!ports) {
45 		*verdict = NF_DROP;
46 		return 0;
47 	}
48 
49 	if (likely(!ip_vs_iph_inverse(iph)))
50 		svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol,
51 					 &iph->daddr, ports[1]);
52 	else
53 		svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol,
54 					 &iph->saddr, ports[0]);
55 	if (svc) {
56 		int ignored;
57 
58 		if (ip_vs_todrop(ipvs)) {
59 			/*
60 			 * It seems that we are very loaded.
61 			 * We have to drop this packet :(
62 			 */
63 			*verdict = NF_DROP;
64 			return 0;
65 		}
66 		/*
67 		 * Let the virtual server select a real server for the
68 		 * incoming connection, and create a connection entry.
69 		 */
70 		*cpp = ip_vs_schedule(svc, skb, pd, &ignored, iph);
71 		if (!*cpp && ignored <= 0) {
72 			if (!ignored)
73 				*verdict = ip_vs_leave(svc, skb, pd, iph);
74 			else
75 				*verdict = NF_DROP;
76 			return 0;
77 		}
78 	}
79 	/* NF_ACCEPT */
80 	return 1;
81 }
82 
83 static void sctp_nat_csum(struct sk_buff *skb, struct sctphdr *sctph,
84 			  unsigned int sctphoff)
85 {
86 	sctph->checksum = sctp_compute_cksum(skb, sctphoff);
87 	skb->ip_summed = CHECKSUM_UNNECESSARY;
88 }
89 
90 static int
91 sctp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
92 		  struct ip_vs_conn *cp, struct ip_vs_iphdr *iph)
93 {
94 	struct sctphdr *sctph;
95 	unsigned int sctphoff = iph->len;
96 	bool payload_csum = false;
97 
98 #ifdef CONFIG_IP_VS_IPV6
99 	if (cp->af == AF_INET6 && iph->fragoffs)
100 		return 1;
101 #endif
102 
103 	/* csum_check requires unshared skb */
104 	if (skb_ensure_writable(skb, sctphoff + sizeof(*sctph)))
105 		return 0;
106 
107 	if (unlikely(cp->app != NULL)) {
108 		int ret;
109 
110 		/* Some checks before mangling */
111 		if (!sctp_csum_check(cp->af, skb, pp))
112 			return 0;
113 
114 		/* Call application helper if needed */
115 		ret = ip_vs_app_pkt_out(cp, skb, iph);
116 		if (ret == 0)
117 			return 0;
118 		/* ret=2: csum update is needed after payload mangling */
119 		if (ret == 2)
120 			payload_csum = true;
121 	}
122 
123 	sctph = (void *) skb_network_header(skb) + sctphoff;
124 
125 	/* Only update csum if we really have to */
126 	if (sctph->source != cp->vport || payload_csum ||
127 	    skb->ip_summed == CHECKSUM_PARTIAL) {
128 		sctph->source = cp->vport;
129 		sctp_nat_csum(skb, sctph, sctphoff);
130 	} else {
131 		skb->ip_summed = CHECKSUM_UNNECESSARY;
132 	}
133 
134 	return 1;
135 }
136 
137 static int
138 sctp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
139 		  struct ip_vs_conn *cp, struct ip_vs_iphdr *iph)
140 {
141 	struct sctphdr *sctph;
142 	unsigned int sctphoff = iph->len;
143 	bool payload_csum = false;
144 
145 #ifdef CONFIG_IP_VS_IPV6
146 	if (cp->af == AF_INET6 && iph->fragoffs)
147 		return 1;
148 #endif
149 
150 	/* csum_check requires unshared skb */
151 	if (skb_ensure_writable(skb, sctphoff + sizeof(*sctph)))
152 		return 0;
153 
154 	if (unlikely(cp->app != NULL)) {
155 		int ret;
156 
157 		/* Some checks before mangling */
158 		if (!sctp_csum_check(cp->af, skb, pp))
159 			return 0;
160 
161 		/* Call application helper if needed */
162 		ret = ip_vs_app_pkt_in(cp, skb, iph);
163 		if (ret == 0)
164 			return 0;
165 		/* ret=2: csum update is needed after payload mangling */
166 		if (ret == 2)
167 			payload_csum = true;
168 	}
169 
170 	sctph = (void *) skb_network_header(skb) + sctphoff;
171 
172 	/* Only update csum if we really have to */
173 	if (sctph->dest != cp->dport || payload_csum ||
174 	    (skb->ip_summed == CHECKSUM_PARTIAL &&
175 	     !(skb_dst(skb)->dev->features & NETIF_F_SCTP_CRC))) {
176 		sctph->dest = cp->dport;
177 		sctp_nat_csum(skb, sctph, sctphoff);
178 	} else if (skb->ip_summed != CHECKSUM_PARTIAL) {
179 		skb->ip_summed = CHECKSUM_UNNECESSARY;
180 	}
181 
182 	return 1;
183 }
184 
185 static int
186 sctp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
187 {
188 	unsigned int sctphoff;
189 	struct sctphdr *sh;
190 	__le32 cmp, val;
191 
192 #ifdef CONFIG_IP_VS_IPV6
193 	if (af == AF_INET6)
194 		sctphoff = sizeof(struct ipv6hdr);
195 	else
196 #endif
197 		sctphoff = ip_hdrlen(skb);
198 
199 	sh = (struct sctphdr *)(skb->data + sctphoff);
200 	cmp = sh->checksum;
201 	val = sctp_compute_cksum(skb, sctphoff);
202 
203 	if (val != cmp) {
204 		/* CRC failure, dump it. */
205 		IP_VS_DBG_RL_PKT(0, af, pp, skb, 0,
206 				"Failed checksum for");
207 		return 0;
208 	}
209 	return 1;
210 }
211 
212 enum ipvs_sctp_event_t {
213 	IP_VS_SCTP_DATA = 0,		/* DATA, SACK, HEARTBEATs */
214 	IP_VS_SCTP_INIT,
215 	IP_VS_SCTP_INIT_ACK,
216 	IP_VS_SCTP_COOKIE_ECHO,
217 	IP_VS_SCTP_COOKIE_ACK,
218 	IP_VS_SCTP_SHUTDOWN,
219 	IP_VS_SCTP_SHUTDOWN_ACK,
220 	IP_VS_SCTP_SHUTDOWN_COMPLETE,
221 	IP_VS_SCTP_ERROR,
222 	IP_VS_SCTP_ABORT,
223 	IP_VS_SCTP_EVENT_LAST
224 };
225 
226 /* RFC 2960, 3.2 Chunk Field Descriptions */
227 static __u8 sctp_events[] = {
228 	[SCTP_CID_DATA]			= IP_VS_SCTP_DATA,
229 	[SCTP_CID_INIT]			= IP_VS_SCTP_INIT,
230 	[SCTP_CID_INIT_ACK]		= IP_VS_SCTP_INIT_ACK,
231 	[SCTP_CID_SACK]			= IP_VS_SCTP_DATA,
232 	[SCTP_CID_HEARTBEAT]		= IP_VS_SCTP_DATA,
233 	[SCTP_CID_HEARTBEAT_ACK]	= IP_VS_SCTP_DATA,
234 	[SCTP_CID_ABORT]		= IP_VS_SCTP_ABORT,
235 	[SCTP_CID_SHUTDOWN]		= IP_VS_SCTP_SHUTDOWN,
236 	[SCTP_CID_SHUTDOWN_ACK]		= IP_VS_SCTP_SHUTDOWN_ACK,
237 	[SCTP_CID_ERROR]		= IP_VS_SCTP_ERROR,
238 	[SCTP_CID_COOKIE_ECHO]		= IP_VS_SCTP_COOKIE_ECHO,
239 	[SCTP_CID_COOKIE_ACK]		= IP_VS_SCTP_COOKIE_ACK,
240 	[SCTP_CID_ECN_ECNE]		= IP_VS_SCTP_DATA,
241 	[SCTP_CID_ECN_CWR]		= IP_VS_SCTP_DATA,
242 	[SCTP_CID_SHUTDOWN_COMPLETE]	= IP_VS_SCTP_SHUTDOWN_COMPLETE,
243 };
244 
245 /* SCTP States:
246  * See RFC 2960, 4. SCTP Association State Diagram
247  *
248  * New states (not in diagram):
249  * - INIT1 state: use shorter timeout for dropped INIT packets
250  * - REJECTED state: use shorter timeout if INIT is rejected with ABORT
251  * - INIT, COOKIE_SENT, COOKIE_REPLIED, COOKIE states: for better debugging
252  *
253  * The states are as seen in real server. In the diagram, INIT1, INIT,
254  * COOKIE_SENT and COOKIE_REPLIED processing happens in CLOSED state.
255  *
256  * States as per packets from client (C) and server (S):
257  *
258  * Setup of client connection:
259  * IP_VS_SCTP_S_INIT1: First C:INIT sent, wait for S:INIT-ACK
260  * IP_VS_SCTP_S_INIT: Next C:INIT sent, wait for S:INIT-ACK
261  * IP_VS_SCTP_S_COOKIE_SENT: S:INIT-ACK sent, wait for C:COOKIE-ECHO
262  * IP_VS_SCTP_S_COOKIE_REPLIED: C:COOKIE-ECHO sent, wait for S:COOKIE-ACK
263  *
264  * Setup of server connection:
265  * IP_VS_SCTP_S_COOKIE_WAIT: S:INIT sent, wait for C:INIT-ACK
266  * IP_VS_SCTP_S_COOKIE: C:INIT-ACK sent, wait for S:COOKIE-ECHO
267  * IP_VS_SCTP_S_COOKIE_ECHOED: S:COOKIE-ECHO sent, wait for C:COOKIE-ACK
268  */
269 
270 #define sNO IP_VS_SCTP_S_NONE
271 #define sI1 IP_VS_SCTP_S_INIT1
272 #define sIN IP_VS_SCTP_S_INIT
273 #define sCS IP_VS_SCTP_S_COOKIE_SENT
274 #define sCR IP_VS_SCTP_S_COOKIE_REPLIED
275 #define sCW IP_VS_SCTP_S_COOKIE_WAIT
276 #define sCO IP_VS_SCTP_S_COOKIE
277 #define sCE IP_VS_SCTP_S_COOKIE_ECHOED
278 #define sES IP_VS_SCTP_S_ESTABLISHED
279 #define sSS IP_VS_SCTP_S_SHUTDOWN_SENT
280 #define sSR IP_VS_SCTP_S_SHUTDOWN_RECEIVED
281 #define sSA IP_VS_SCTP_S_SHUTDOWN_ACK_SENT
282 #define sRJ IP_VS_SCTP_S_REJECTED
283 #define sCL IP_VS_SCTP_S_CLOSED
284 
285 static const __u8 sctp_states
286 	[IP_VS_DIR_LAST][IP_VS_SCTP_EVENT_LAST][IP_VS_SCTP_S_LAST] = {
287 	{ /* INPUT */
288 /*        sNO, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL*/
289 /* d   */{sES, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
290 /* i   */{sI1, sIN, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sIN, sIN},
291 /* i_a */{sCW, sCW, sCW, sCS, sCR, sCO, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
292 /* c_e */{sCR, sIN, sIN, sCR, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
293 /* c_a */{sES, sI1, sIN, sCS, sCR, sCW, sCO, sES, sES, sSS, sSR, sSA, sRJ, sCL},
294 /* s   */{sSR, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sSR, sSS, sSR, sSA, sRJ, sCL},
295 /* s_a */{sCL, sIN, sIN, sCS, sCR, sCW, sCO, sCE, sES, sCL, sSR, sCL, sRJ, sCL},
296 /* s_c */{sCL, sCL, sCL, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sCL, sRJ, sCL},
297 /* err */{sCL, sI1, sIN, sCS, sCR, sCW, sCO, sCL, sES, sSS, sSR, sSA, sRJ, sCL},
298 /* ab  */{sCL, sCL, sCL, sCL, sCL, sRJ, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
299 	},
300 	{ /* OUTPUT */
301 /*        sNO, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL*/
302 /* d   */{sES, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
303 /* i   */{sCW, sCW, sCW, sCW, sCW, sCW, sCW, sCW, sES, sCW, sCW, sCW, sCW, sCW},
304 /* i_a */{sCS, sCS, sCS, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
305 /* c_e */{sCE, sCE, sCE, sCE, sCE, sCE, sCE, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
306 /* c_a */{sES, sES, sES, sES, sES, sES, sES, sES, sES, sSS, sSR, sSA, sRJ, sCL},
307 /* s   */{sSS, sSS, sSS, sSS, sSS, sSS, sSS, sSS, sSS, sSS, sSR, sSA, sRJ, sCL},
308 /* s_a */{sSA, sSA, sSA, sSA, sSA, sCW, sCO, sCE, sES, sSA, sSA, sSA, sRJ, sCL},
309 /* s_c */{sCL, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
310 /* err */{sCL, sCL, sCL, sCL, sCL, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
311 /* ab  */{sCL, sRJ, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
312 	},
313 	{ /* INPUT-ONLY */
314 /*        sNO, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL*/
315 /* d   */{sES, sI1, sIN, sCS, sCR, sES, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
316 /* i   */{sI1, sIN, sIN, sIN, sIN, sIN, sCO, sCE, sES, sSS, sSR, sSA, sIN, sIN},
317 /* i_a */{sCE, sCE, sCE, sCE, sCE, sCE, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
318 /* c_e */{sES, sES, sES, sES, sES, sES, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
319 /* c_a */{sES, sI1, sIN, sES, sES, sCW, sES, sES, sES, sSS, sSR, sSA, sRJ, sCL},
320 /* s   */{sSR, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sSR, sSS, sSR, sSA, sRJ, sCL},
321 /* s_a */{sCL, sIN, sIN, sCS, sCR, sCW, sCO, sCE, sCL, sCL, sSR, sCL, sRJ, sCL},
322 /* s_c */{sCL, sCL, sCL, sCL, sCL, sCW, sCO, sCE, sES, sSS, sCL, sCL, sRJ, sCL},
323 /* err */{sCL, sI1, sIN, sCS, sCR, sCW, sCO, sCE, sES, sSS, sSR, sSA, sRJ, sCL},
324 /* ab  */{sCL, sCL, sCL, sCL, sCL, sRJ, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
325 	},
326 };
327 
328 #define IP_VS_SCTP_MAX_RTO	((60 + 1) * HZ)
329 
330 /* Timeout table[state] */
331 static const int sctp_timeouts[IP_VS_SCTP_S_LAST + 1] = {
332 	[IP_VS_SCTP_S_NONE]			= 2 * HZ,
333 	[IP_VS_SCTP_S_INIT1]			= (0 + 3 + 1) * HZ,
334 	[IP_VS_SCTP_S_INIT]			= IP_VS_SCTP_MAX_RTO,
335 	[IP_VS_SCTP_S_COOKIE_SENT]		= IP_VS_SCTP_MAX_RTO,
336 	[IP_VS_SCTP_S_COOKIE_REPLIED]		= IP_VS_SCTP_MAX_RTO,
337 	[IP_VS_SCTP_S_COOKIE_WAIT]		= IP_VS_SCTP_MAX_RTO,
338 	[IP_VS_SCTP_S_COOKIE]			= IP_VS_SCTP_MAX_RTO,
339 	[IP_VS_SCTP_S_COOKIE_ECHOED]		= IP_VS_SCTP_MAX_RTO,
340 	[IP_VS_SCTP_S_ESTABLISHED]		= 15 * 60 * HZ,
341 	[IP_VS_SCTP_S_SHUTDOWN_SENT]		= IP_VS_SCTP_MAX_RTO,
342 	[IP_VS_SCTP_S_SHUTDOWN_RECEIVED]	= IP_VS_SCTP_MAX_RTO,
343 	[IP_VS_SCTP_S_SHUTDOWN_ACK_SENT]	= IP_VS_SCTP_MAX_RTO,
344 	[IP_VS_SCTP_S_REJECTED]			= (0 + 3 + 1) * HZ,
345 	[IP_VS_SCTP_S_CLOSED]			= IP_VS_SCTP_MAX_RTO,
346 	[IP_VS_SCTP_S_LAST]			= 2 * HZ,
347 };
348 
349 static const char *sctp_state_name_table[IP_VS_SCTP_S_LAST + 1] = {
350 	[IP_VS_SCTP_S_NONE]			= "NONE",
351 	[IP_VS_SCTP_S_INIT1]			= "INIT1",
352 	[IP_VS_SCTP_S_INIT]			= "INIT",
353 	[IP_VS_SCTP_S_COOKIE_SENT]		= "C-SENT",
354 	[IP_VS_SCTP_S_COOKIE_REPLIED]		= "C-REPLIED",
355 	[IP_VS_SCTP_S_COOKIE_WAIT]		= "C-WAIT",
356 	[IP_VS_SCTP_S_COOKIE]			= "COOKIE",
357 	[IP_VS_SCTP_S_COOKIE_ECHOED]		= "C-ECHOED",
358 	[IP_VS_SCTP_S_ESTABLISHED]		= "ESTABLISHED",
359 	[IP_VS_SCTP_S_SHUTDOWN_SENT]		= "S-SENT",
360 	[IP_VS_SCTP_S_SHUTDOWN_RECEIVED]	= "S-RECEIVED",
361 	[IP_VS_SCTP_S_SHUTDOWN_ACK_SENT]	= "S-ACK-SENT",
362 	[IP_VS_SCTP_S_REJECTED]			= "REJECTED",
363 	[IP_VS_SCTP_S_CLOSED]			= "CLOSED",
364 	[IP_VS_SCTP_S_LAST]			= "BUG!",
365 };
366 
367 
368 static const char *sctp_state_name(int state)
369 {
370 	if (state >= IP_VS_SCTP_S_LAST)
371 		return "ERR!";
372 	if (sctp_state_name_table[state])
373 		return sctp_state_name_table[state];
374 	return "?";
375 }
376 
377 static inline void
378 set_sctp_state(struct ip_vs_proto_data *pd, struct ip_vs_conn *cp,
379 		int direction, const struct sk_buff *skb)
380 {
381 	struct sctp_chunkhdr _sctpch, *sch;
382 	unsigned char chunk_type;
383 	int event, next_state;
384 	int ihl, cofs;
385 
386 #ifdef CONFIG_IP_VS_IPV6
387 	ihl = cp->af == AF_INET ? ip_hdrlen(skb) : sizeof(struct ipv6hdr);
388 #else
389 	ihl = ip_hdrlen(skb);
390 #endif
391 
392 	cofs = ihl + sizeof(struct sctphdr);
393 	sch = skb_header_pointer(skb, cofs, sizeof(_sctpch), &_sctpch);
394 	if (sch == NULL)
395 		return;
396 
397 	chunk_type = sch->type;
398 	/*
399 	 * Section 3: Multiple chunks can be bundled into one SCTP packet
400 	 * up to the MTU size, except for the INIT, INIT ACK, and
401 	 * SHUTDOWN COMPLETE chunks. These chunks MUST NOT be bundled with
402 	 * any other chunk in a packet.
403 	 *
404 	 * Section 3.3.7: DATA chunks MUST NOT be bundled with ABORT. Control
405 	 * chunks (except for INIT, INIT ACK, and SHUTDOWN COMPLETE) MAY be
406 	 * bundled with an ABORT, but they MUST be placed before the ABORT
407 	 * in the SCTP packet or they will be ignored by the receiver.
408 	 */
409 	if ((sch->type == SCTP_CID_COOKIE_ECHO) ||
410 	    (sch->type == SCTP_CID_COOKIE_ACK)) {
411 		int clen = ntohs(sch->length);
412 
413 		if (clen >= sizeof(_sctpch)) {
414 			sch = skb_header_pointer(skb, cofs + ALIGN(clen, 4),
415 						 sizeof(_sctpch), &_sctpch);
416 			if (sch && sch->type == SCTP_CID_ABORT)
417 				chunk_type = sch->type;
418 		}
419 	}
420 
421 	event = (chunk_type < sizeof(sctp_events)) ?
422 		sctp_events[chunk_type] : IP_VS_SCTP_DATA;
423 
424 	/* Update direction to INPUT_ONLY if necessary
425 	 * or delete NO_OUTPUT flag if output packet detected
426 	 */
427 	if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
428 		if (direction == IP_VS_DIR_OUTPUT)
429 			cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
430 		else
431 			direction = IP_VS_DIR_INPUT_ONLY;
432 	}
433 
434 	next_state = sctp_states[direction][event][cp->state];
435 
436 	if (next_state != cp->state) {
437 		struct ip_vs_dest *dest = cp->dest;
438 
439 		IP_VS_DBG_BUF(8, "%s %s  %s:%d->"
440 				"%s:%d state: %s->%s conn->refcnt:%d\n",
441 				pd->pp->name,
442 				((direction == IP_VS_DIR_OUTPUT) ?
443 				 "output " : "input "),
444 				IP_VS_DBG_ADDR(cp->daf, &cp->daddr),
445 				ntohs(cp->dport),
446 				IP_VS_DBG_ADDR(cp->af, &cp->caddr),
447 				ntohs(cp->cport),
448 				sctp_state_name(cp->state),
449 				sctp_state_name(next_state),
450 				refcount_read(&cp->refcnt));
451 		if (dest) {
452 			if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
453 				(next_state != IP_VS_SCTP_S_ESTABLISHED)) {
454 				atomic_dec(&dest->activeconns);
455 				atomic_inc(&dest->inactconns);
456 				cp->flags |= IP_VS_CONN_F_INACTIVE;
457 			} else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
458 				   (next_state == IP_VS_SCTP_S_ESTABLISHED)) {
459 				atomic_inc(&dest->activeconns);
460 				atomic_dec(&dest->inactconns);
461 				cp->flags &= ~IP_VS_CONN_F_INACTIVE;
462 			}
463 		}
464 		if (next_state == IP_VS_SCTP_S_ESTABLISHED)
465 			ip_vs_control_assure_ct(cp);
466 	}
467 	if (likely(pd))
468 		cp->timeout = pd->timeout_table[cp->state = next_state];
469 	else	/* What to do ? */
470 		cp->timeout = sctp_timeouts[cp->state = next_state];
471 }
472 
473 static void
474 sctp_state_transition(struct ip_vs_conn *cp, int direction,
475 		const struct sk_buff *skb, struct ip_vs_proto_data *pd)
476 {
477 	spin_lock_bh(&cp->lock);
478 	set_sctp_state(pd, cp, direction, skb);
479 	spin_unlock_bh(&cp->lock);
480 }
481 
482 static inline __u16 sctp_app_hashkey(__be16 port)
483 {
484 	return (((__force u16)port >> SCTP_APP_TAB_BITS) ^ (__force u16)port)
485 		& SCTP_APP_TAB_MASK;
486 }
487 
488 static int sctp_register_app(struct netns_ipvs *ipvs, struct ip_vs_app *inc)
489 {
490 	struct ip_vs_app *i;
491 	__u16 hash;
492 	__be16 port = inc->port;
493 	int ret = 0;
494 	struct ip_vs_proto_data *pd = ip_vs_proto_data_get(ipvs, IPPROTO_SCTP);
495 
496 	hash = sctp_app_hashkey(port);
497 
498 	list_for_each_entry(i, &ipvs->sctp_apps[hash], p_list) {
499 		if (i->port == port) {
500 			ret = -EEXIST;
501 			goto out;
502 		}
503 	}
504 	list_add_rcu(&inc->p_list, &ipvs->sctp_apps[hash]);
505 	atomic_inc(&pd->appcnt);
506 out:
507 
508 	return ret;
509 }
510 
511 static void sctp_unregister_app(struct netns_ipvs *ipvs, struct ip_vs_app *inc)
512 {
513 	struct ip_vs_proto_data *pd = ip_vs_proto_data_get(ipvs, IPPROTO_SCTP);
514 
515 	atomic_dec(&pd->appcnt);
516 	list_del_rcu(&inc->p_list);
517 }
518 
519 static int sctp_app_conn_bind(struct ip_vs_conn *cp)
520 {
521 	struct netns_ipvs *ipvs = cp->ipvs;
522 	int hash;
523 	struct ip_vs_app *inc;
524 	int result = 0;
525 
526 	/* Default binding: bind app only for NAT */
527 	if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
528 		return 0;
529 	/* Lookup application incarnations and bind the right one */
530 	hash = sctp_app_hashkey(cp->vport);
531 
532 	list_for_each_entry_rcu(inc, &ipvs->sctp_apps[hash], p_list) {
533 		if (inc->port == cp->vport) {
534 			if (unlikely(!ip_vs_app_inc_get(inc)))
535 				break;
536 
537 			IP_VS_DBG_BUF(9, "%s: Binding conn %s:%u->"
538 					"%s:%u to app %s on port %u\n",
539 					__func__,
540 					IP_VS_DBG_ADDR(cp->af, &cp->caddr),
541 					ntohs(cp->cport),
542 					IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
543 					ntohs(cp->vport),
544 					inc->name, ntohs(inc->port));
545 			cp->app = inc;
546 			if (inc->init_conn)
547 				result = inc->init_conn(inc, cp);
548 			break;
549 		}
550 	}
551 
552 	return result;
553 }
554 
555 /* ---------------------------------------------
556  *   timeouts is netns related now.
557  * ---------------------------------------------
558  */
559 static int __ip_vs_sctp_init(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd)
560 {
561 	ip_vs_init_hash_table(ipvs->sctp_apps, SCTP_APP_TAB_SIZE);
562 	pd->timeout_table = ip_vs_create_timeout_table((int *)sctp_timeouts,
563 							sizeof(sctp_timeouts));
564 	if (!pd->timeout_table)
565 		return -ENOMEM;
566 	return 0;
567 }
568 
569 static void __ip_vs_sctp_exit(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd)
570 {
571 	kfree(pd->timeout_table);
572 }
573 
574 struct ip_vs_protocol ip_vs_protocol_sctp = {
575 	.name		= "SCTP",
576 	.protocol	= IPPROTO_SCTP,
577 	.num_states	= IP_VS_SCTP_S_LAST,
578 	.dont_defrag	= 0,
579 	.init		= NULL,
580 	.exit		= NULL,
581 	.init_netns	= __ip_vs_sctp_init,
582 	.exit_netns	= __ip_vs_sctp_exit,
583 	.register_app	= sctp_register_app,
584 	.unregister_app = sctp_unregister_app,
585 	.conn_schedule	= sctp_conn_schedule,
586 	.conn_in_get	= ip_vs_conn_in_get_proto,
587 	.conn_out_get	= ip_vs_conn_out_get_proto,
588 	.snat_handler	= sctp_snat_handler,
589 	.dnat_handler	= sctp_dnat_handler,
590 	.state_name	= sctp_state_name,
591 	.state_transition = sctp_state_transition,
592 	.app_conn_bind	= sctp_app_conn_bind,
593 	.debug_packet	= ip_vs_tcpudp_debug_packet,
594 	.timeout_change	= NULL,
595 };
596