1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		PF_INET6 protocol dispatch tables.
7  *
8  * Version:	$Id: protocol.c,v 1.10 2001/05/18 02:25:49 davem Exp $
9  *
10  * Authors:	Pedro Roque	<pedro_m@yahoo.com>
11  *
12  *		This program is free software; you can redistribute it and/or
13  *		modify it under the terms of the GNU General Public License
14  *		as published by the Free Software Foundation; either version
15  *		2 of the License, or (at your option) any later version.
16  */
17 
18 /*
19  *      Changes:
20  *
21  *      Vince Laviano (vince@cs.stanford.edu)       16 May 2001
22  *      - Removed unused variable 'inet6_protocol_base'
23  *      - Modified inet6_del_protocol() to correctly maintain copy bit.
24  */
25 
26 #include <linux/errno.h>
27 #include <linux/types.h>
28 #include <linux/socket.h>
29 #include <linux/sockios.h>
30 #include <linux/sched.h>
31 #include <linux/net.h>
32 #include <linux/in6.h>
33 #include <linux/netdevice.h>
34 #include <linux/if_arp.h>
35 #include <linux/brlock.h>
36 
37 #include <net/sock.h>
38 #include <net/snmp.h>
39 
40 #include <net/ipv6.h>
41 #include <net/protocol.h>
42 
43 struct inet6_protocol *inet6_protos[MAX_INET_PROTOS];
44 
inet6_add_protocol(struct inet6_protocol * prot)45 void inet6_add_protocol(struct inet6_protocol *prot)
46 {
47 	unsigned char hash;
48 	struct inet6_protocol *p2;
49 
50 	hash = prot->protocol & (MAX_INET_PROTOS - 1);
51 	br_write_lock_bh(BR_NETPROTO_LOCK);
52 	prot->next = inet6_protos[hash];
53 	inet6_protos[hash] = prot;
54 	prot->copy = 0;
55 
56 	/*
57 	 *	Set the copy bit if we need to.
58 	 */
59 
60 	p2 = (struct inet6_protocol *) prot->next;
61 	while(p2 != NULL) {
62 		if (p2->protocol == prot->protocol) {
63 			prot->copy = 1;
64 			break;
65 		}
66 		p2 = (struct inet6_protocol *) p2->next;
67 	}
68 	br_write_unlock_bh(BR_NETPROTO_LOCK);
69 }
70 
71 /*
72  *	Remove a protocol from the hash tables.
73  */
74 
inet6_del_protocol(struct inet6_protocol * prot)75 int inet6_del_protocol(struct inet6_protocol *prot)
76 {
77 	struct inet6_protocol *p;
78 	struct inet6_protocol *lp = NULL;
79 	unsigned char hash;
80 
81 	hash = prot->protocol & (MAX_INET_PROTOS - 1);
82 	br_write_lock_bh(BR_NETPROTO_LOCK);
83 	if (prot == inet6_protos[hash]) {
84 		inet6_protos[hash] = (struct inet6_protocol *) inet6_protos[hash]->next;
85 		br_write_unlock_bh(BR_NETPROTO_LOCK);
86 		return(0);
87 	}
88 
89 	p = (struct inet6_protocol *) inet6_protos[hash];
90 
91         if (p != NULL && p->protocol == prot->protocol)
92                 lp = p;
93 
94 	while(p != NULL) {
95 		/*
96 		 * We have to worry if the protocol being deleted is
97 		 * the last one on the list, then we may need to reset
98 		 * someone's copied bit.
99 		 */
100 		if (p->next != NULL && p->next == prot) {
101 			/*
102 			 * if we are the last one with this protocol and
103 			 * there is a previous one, reset its copy bit.
104 			 */
105 			if (prot->copy == 0 && lp != NULL)
106 				lp->copy = 0;
107 			p->next = prot->next;
108 			br_write_unlock_bh(BR_NETPROTO_LOCK);
109 			return(0);
110 		}
111 		if (p->next != NULL && p->next->protocol == prot->protocol)
112 			lp = p->next;
113 
114 		p = (struct inet6_protocol *) p->next;
115 	}
116 	br_write_unlock_bh(BR_NETPROTO_LOCK);
117 	return(-1);
118 }
119