1 /*
2 * Copyright 1997 Massachusetts Institute of Technology
3 *
4 * Permission to use, copy, modify, and distribute this software and
5 * its documentation for any purpose and without fee is hereby
6 * granted, provided that both the above copyright notice and this
7 * permission notice appear in all copies, that both the above
8 * copyright notice and this permission notice appear in all
9 * supporting documentation, and that the name of M.I.T. not be used
10 * in advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission. M.I.T. makes
12 * no representations about the suitability of this software for any
13 * purpose. It is provided "as is" without express or implied
14 * warranty.
15 *
16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/malloc.h>
35 #include <sys/socket.h>
36 #include <sys/socketvar.h>
37
38 #include <net/hostcache.h>
39 #include <net/if.h>
40 #include <net/if_var.h>
41 #include <net/route.h>
42
43 #include <netinet/in.h>
44 #include <netinet/in_hostcache.h>
45 #include <netinet/tcp.h>
46 #include <netinet/tcp_timer.h>
47 #include <netinet/tcp_var.h>
48
49 /*
50 * Manage the IP per-host cache (really a thin veneer over the generic
51 * per-host cache code).
52 */
53
54 /* Look up an entry -- can be called from interrupt context. */
55 struct in_hcentry *
56 inhc_lookup(struct sockaddr_in *sin)
57 {
58 struct hcentry *hc;
59
60 hc = hc_get((struct sockaddr *)sin);
61 return ((struct in_hcentry *)hc);
62 }
63
64 /* Look up and possibly create an entry -- must be called from user mode. */
65 struct in_hcentry *
66 inhc_alloc(struct sockaddr_in *sin)
67 {
68 struct in_hcentry *inhc;
69 struct rtentry *rt;
70 int error;
71 /* xxx mutual exclusion for smp */
72
73 inhc = inhc_lookup(sin);
74 if (inhc != 0)
75 return inhc;
76
77 rt = rtalloc1(inhc->inhc_hc.hc_host, 1, 0);
78 if (rt == 0)
79 return 0;
80
81 MALLOC(inhc, struct in_hcentry *, sizeof *inhc, M_HOSTCACHE, M_WAITOK);
82 bzero(inhc, sizeof *inhc);
83 inhc->inhc_hc.hc_host = dup_sockaddr((struct sockaddr *)sin, 1);
84 if (in_broadcast(sin->sin_addr, rt->rt_ifp))
85 inhc->inhc_flags |= INHC_BROADCAST;
86 else if (((struct sockaddr_in *)rt->rt_ifa->ifa_addr)->sin_addr.s_addr
87 == sin->sin_addr.s_addr)
88 inhc->inhc_flags |= INHC_LOCAL;
89 else if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
90 inhc->inhc_flags |= INHC_MULTICAST;
91 inhc->inhc_pmtu = rt->rt_rmx.rmx_mtu;
92 inhc->inhc_recvpipe = rt->rt_rmx.rmx_recvpipe;
93 inhc->inhc_sendpipe = rt->rt_rmx.rmx_sendpipe;
94 inhc->inhc_ssthresh = rt->rt_rmx.rmx_ssthresh;
95 if (rt->rt_rmx.rmx_locks & RTV_RTT)
96 inhc->inhc_rttmin = rt->rt_rmx.rmx_rtt
97 / (RTM_RTTUNIT / TCP_RTT_SCALE);
98 inhc->inhc_hc.hc_rt = rt;
99 error = hc_insert(&inhc->inhc_hc);
100 if (error != 0) {
101 RTFREE(rt);
102 FREE(inhc, M_HOSTCACHE);
103 return 0;
104 }
105 /*
106 * We don't return the structure directly because hc_get() needs
107 * to be allowed to do its own processing.
108 */
109 return (inhc_lookup(sin));
110 }
111
112 /*
113 * This is Van Jacobson's hash function for IPv4 addresses.
114 * It is designed to work with a power-of-two-sized hash table.
115 */
116 static u_long
117 inhc_hash(struct sockaddr *sa, u_long nbuckets)
118 {
119 u_long ip;
120
121 ip = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
122 return ((ip ^ (ip >> 23) ^ (ip >> 17)) & ~(nbuckets - 1));
123 }
124
125 /*
126 * We don't need to do any special work... if there are no references,
127 * as the caller has already ensured, then it's OK to kill.
128 */
129 static int
130 inhc_delete(struct hcentry *hc)
131 {
132 return 0;
133 }
134
135 /*
136 * Return the next increment for the number of buckets in the hash table.
137 * Zero means ``do not bump''.
138 */
139 static u_long
140 inhc_bump(u_long oldsize)
141 {
142 if (oldsize < 512)
143 return (oldsize << 1);
144 return 0;
145 }
146
147 static struct hccallback inhc_cb = {
148 inhc_hash, inhc_delete, inhc_bump
149 };
150
151 int
152 inhc_init(void)
153 {
154
155 return (hc_init(AF_INET, &inhc_cb, 128, 0));
156 }
157
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