sctp: delete the nested flexible array params

This patch deletes the flexible-array params[] from the structure
sctp_inithdr, sctp_addiphdr and sctp_reconf_chunk to avoid some
sparse warnings:

  # make C=2 CF="-Wflexible-array-nested" M=./net/sctp/
  net/sctp/input.c: note: in included file (through include/net/sctp/structs.h, include/net/sctp/sctp.h):
  ./include/linux/sctp.h:278:29: warning: nested flexible array
  ./include/linux/sctp.h:675:30: warning: nested flexible array

This warning is reported if a structure having a flexible array
member is included by other structures.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/sctp.h

@@ -270,7 +270,7 @@ struct sctp_inithdr {
 	__be16 num_outbound_streams;
 	__be16 num_inbound_streams;
 	__be32 initial_tsn;
-	__u8  params[];
+	/* __u8  params[]; */
 };
 
 struct sctp_init_chunk {
@@ -667,7 +667,7 @@ struct sctp_addip_param {
 
 struct sctp_addiphdr {
 	__be32	serial;
-	__u8	params[];
+	/* __u8	params[]; */
 };
 
 struct sctp_addip_chunk {
@@ -742,7 +742,7 @@ struct sctp_infox {
 
 struct sctp_reconf_chunk {
 	struct sctp_chunkhdr chunk_hdr;
-	__u8 params[];
+	/* __u8 params[]; */
 };
 
 struct sctp_strreset_outreq {

include/net/sctp/sctp.h

@@ -425,11 +425,11 @@ static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
  * 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)\
+_sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length))
 
-#define _sctp_walk_params(pos, chunk, end, member)\
-for (pos.v = chunk->member;\
+#define _sctp_walk_params(pos, chunk, end)\
+for (pos.v = (u8 *)(chunk + 1);\
      (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
       (void *)chunk + end) &&\
      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\

net/sctp/input.c

@@ -1150,7 +1150,7 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
 	init = (struct sctp_init_chunk *)skb->data;
 
 	/* Walk the parameters looking for embedded addresses. */
-	sctp_walk_params(params, init, init_hdr.params) {
+	sctp_walk_params(params, init) {
 
 		/* Note: Ignoring hostname addresses. */
 		af = sctp_get_af_specific(param_type2af(params.p->type));

net/sctp/sm_make_chunk.c

@@ -2306,7 +2306,7 @@ int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
 	    ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
 		return sctp_process_inv_mandatory(asoc, chunk, errp);
 
-	sctp_walk_params(param, peer_init, init_hdr.params) {
+	sctp_walk_params(param, peer_init) {
 		if (param.p->type == SCTP_PARAM_STATE_COOKIE)
 			has_cookie = true;
 	}
@@ -2329,7 +2329,7 @@ int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
 						  chunk, errp);
 
 	/* Verify all the variable length parameters */
-	sctp_walk_params(param, peer_init, init_hdr.params) {
+	sctp_walk_params(param, peer_init) {
 		result = sctp_verify_param(net, ep, asoc, param, cid,
 					   chunk, errp);
 		switch (result) {
@@ -2381,7 +2381,7 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
 		src_match = 1;
 
 	/* Process the initialization parameters.  */
-	sctp_walk_params(param, peer_init, init_hdr.params) {
+	sctp_walk_params(param, peer_init) {
 		if (!src_match &&
 		    (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
 		     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
@@ -3202,7 +3202,7 @@ bool sctp_verify_asconf(const struct sctp_association *asoc,
 	union sctp_params param;
 
 	addip = (struct sctp_addip_chunk *)chunk->chunk_hdr;
-	sctp_walk_params(param, addip, addip_hdr.params) {
+	sctp_walk_params(param, addip) {
 		size_t length = ntohs(param.p->length);
 
 		*errp = param.p;
@@ -3215,14 +3215,14 @@ bool sctp_verify_asconf(const struct sctp_association *asoc,
 			/* ensure there is only one addr param and it's in the
 			 * beginning of addip_hdr params, or we reject it.
 			 */
-			if (param.v != addip->addip_hdr.params)
+			if (param.v != (addip + 1))
 				return false;
 			addr_param_seen = true;
 			break;
 		case SCTP_PARAM_IPV6_ADDRESS:
 			if (length != sizeof(struct sctp_ipv6addr_param))
 				return false;
-			if (param.v != addip->addip_hdr.params)
+			if (param.v != (addip + 1))
 				return false;
 			addr_param_seen = true;
 			break;
@@ -3302,7 +3302,7 @@ struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
 		goto done;
 
 	/* Process the TLVs contained within the ASCONF chunk. */
-	sctp_walk_params(param, addip, addip_hdr.params) {
+	sctp_walk_params(param, addip) {
 		/* Skip preceeding address parameters. */
 		if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)
@@ -3636,7 +3636,7 @@ static struct sctp_chunk *sctp_make_reconf(const struct sctp_association *asoc,
 		return NULL;
 
 	reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
-	retval->param_hdr.v = reconf->params;
+	retval->param_hdr.v = (u8 *)(reconf + 1);
 
 	return retval;
 }
@@ -3878,7 +3878,7 @@ bool sctp_verify_reconf(const struct sctp_association *asoc,
 	__u16 cnt = 0;
 
 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
-	sctp_walk_params(param, hdr, params) {
+	sctp_walk_params(param, hdr) {
 		__u16 length = ntohs(param.p->length);
 
 		*errp = param.p;

net/sctp/sm_statefuns.c

@@ -4142,7 +4142,7 @@ enum sctp_disposition sctp_sf_do_reconf(struct net *net,
 						  (void *)err_param, commands);
 
 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
-	sctp_walk_params(param, hdr, params) {
+	sctp_walk_params(param, hdr) {
 		struct sctp_chunk *reply = NULL;
 		struct sctp_ulpevent *ev = NULL;
 

net/sctp/stream.c

@@ -491,7 +491,7 @@ static struct sctp_paramhdr *sctp_chunk_lookup_strreset_param(
 		return NULL;
 
 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
-	sctp_walk_params(param, hdr, params) {
+	sctp_walk_params(param, hdr) {
 		/* sctp_strreset_tsnreq is actually the basic structure
 		 * of all stream reconf params, so it's safe to use it
 		 * to access request_seq.