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1.1 root 1: /*
2: * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution is only permitted until one year after the first shipment
6: * of 4.4BSD by the Regents. Otherwise, redistribution and use in source and
7: * binary forms are permitted provided that: (1) source distributions retain
8: * this entire copyright notice and comment, and (2) distributions including
9: * binaries display the following acknowledgement: This product includes
10: * software developed by the University of California, Berkeley and its
11: * contributors'' in the documentation or other materials provided with the
12: * distribution and in all advertising materials mentioning features or use
13: * of this software. Neither the name of the University nor the names of
14: * its contributors may be used to endorse or promote products derived from
15: * this software without specific prior written permission.
16: * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
17: * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
18: * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19: *
20: * @(#)if_imphost.h 7.7 (Berkeley) 6/28/90
21: */
22:
23: /*
24: * Host structure used with IMP's.
25: * Used to hold outgoing packets which
26: * would exceed allowed RFNM count.
27: *
28: * These structures are packed into
29: * mbuf's and kept as small as possible.
30: */
31: struct host {
32: struct mbuf *h_q; /* holding queue */
33: u_short h_timer; /* used to stay off deletion */
34: u_short h_imp; /* host's imp number */
35: u_char h_host; /* host's number on imp */
36: u_char h_qcnt; /* size of holding q */
37: u_char h_rfnm; /* # outstanding rfnm's */
38: u_char h_flags; /* see below */
39: };
40:
41: /*
42: * A host structure is kept around (even when there are no
43: * references to it) for a spell to avoid constant reallocation
44: * and also to reflect IMP status back to sites which aren't
45: * directly connected to the IMP. When structures are marked
46: * idle, a timer is started; when the timer expires the structure
47: * is deallocated. A structure may be reused before the timer expires.
48: * A structure holds a reference on the containing mbuf when it is marked
49: * HF_INUSE.
50: */
51: #define HF_INUSE 0x1
52: #define HF_DEAD (1<<IMPTYPE_HOSTDEAD)
53: #define HF_UNREACH (1<<IMPTYPE_HOSTUNREACH)
54:
55: #define HOSTTIMER 128 /* keep structure around awhile */
56:
57: /*
58: * Mark a host structure free; used if host entry returned by hostlookup
59: * isn't needed. h_rfnm must be zero.
60: */
61: #define hostfree(hp) { \
62: if ((hp)->h_timer == 0 && (hp)->h_qcnt == 0 && \
63: (hp)->h_flags & HF_INUSE) \
64: hostrelease(hp); \
65: }
66:
67: /*
68: * Release a host entry when last rfnm is received.
69: */
70: #define hostidle(hp) { (hp)->h_timer = HOSTTIMER; }
71:
72: /*
73: * Host structures, as seen inside an mbuf.
74: * Hashing on the host and imp is used to
75: * select an index into the first mbuf. Collisions
76: * are then resolved by searching successive
77: * mbuf's at the same index. Reclamation is done
78: * automatically at the time a structure is freed.
79: */
80: #define HPMBUF ((MLEN - sizeof(int)) / sizeof(struct host))
81: /* don't need to swab as long as HPMBUF is odd */
82: #if defined(notdef) && BYTE_ORDER == BIG_ENDIAN
83: #define HOSTHASH(imp, host) ((unsigned)(ntohs(imp)+(host)) % HPMBUF)
84: #else
85: #define HOSTHASH(imp, host) ((unsigned)((imp)+(host)) % HPMBUF)
86: #endif
87:
88: /*
89: * In-line expansions for queuing operations on
90: * host message holding queue. Queue is maintained
91: * as circular list with the head pointing to the
92: * last message in the queue.
93: */
94: #define HOST_ENQUE(hp, m) { \
95: register struct mbuf *n; \
96: (hp)->h_qcnt++; \
97: if ((n = (hp)->h_q) == 0) \
98: (hp)->h_q = (m)->m_act = (m); \
99: else { \
100: (m)->m_act = n->m_act; \
101: (hp)->h_q = n->m_act = (m); \
102: } \
103: }
104: #define HOST_DEQUE(hp, m) { \
105: if ((m) = (hp)->h_q) { \
106: if ((m)->m_act == (m)) \
107: (hp)->h_q = 0; \
108: else { \
109: (m) = (m)->m_act; \
110: (hp)->h_q->m_act = (m)->m_act; \
111: } \
112: (hp)->h_qcnt--; \
113: (m)->m_act = 0; \
114: } \
115: }
116:
117: struct hmbuf {
118: int hm_count; /* # of struct's in use */
119: struct host hm_hosts[HPMBUF]; /* data structures proper */
120: };
121:
122: #ifdef KERNEL
123: struct host *hostlookup();
124: struct host *hostenter();
125: #endif
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