1 /* if_imphost.h 6.1 83/07/29 */ 2 3 /* 4 * Host structure used with IMP's. 5 * Used to hold outgoing packets which 6 * would exceed allowed RFNM count. 7 * 8 * These structures are packed into 9 * mbuf's and kept as small as possible. 10 */ 11 struct host { 12 struct mbuf *h_q; /* holding queue */ 13 struct in_addr h_addr; /* host's address */ 14 u_char h_qcnt; /* size of holding q */ 15 u_char h_timer; /* used to stay off deletion */ 16 u_char h_rfnm; /* # outstanding rfnm's */ 17 u_char h_flags; /* see below */ 18 }; 19 20 /* 21 * A host structure is kept around (even when there are no 22 * references to it) for a spell to avoid constant reallocation 23 * and also to reflect IMP status back to sites which aren't 24 * directly connected to the IMP. When structures are marked 25 * free, a timer is started; when the timer expires the structure 26 * is scavenged. 27 */ 28 #define HF_INUSE 0x1 29 #define HF_DEAD (1<<IMPTYPE_HOSTDEAD) 30 #define HF_UNREACH (1<<IMPTYPE_HOSTUNREACH) 31 32 #define HOSTTIMER 128 /* keep structure around awhile */ 33 34 /* 35 * Host structures, as seen inside an mbuf. 36 * Hashing on the host address is used to 37 * select an index into the first mbuf. Collisions 38 * are then resolved by searching successive 39 * mbuf's at the same index. Reclamation is done 40 * automatically at the time a structure is free'd. 41 */ 42 #define HPMBUF ((MLEN - sizeof(int)) / sizeof(struct host)) 43 #if vax 44 #define HOSTHASH(a) ((((a).s_addr>>8)+(a).s_net) % HPMBUF) 45 #endif 46 47 /* 48 * In-line expansions for queuing operations on 49 * host message holding queue. Queue is maintained 50 * as circular list with the head pointing to the 51 * last message in the queue. 52 */ 53 #define HOST_ENQUE(hp, m) { \ 54 register struct mbuf *n; \ 55 (hp)->h_qcnt++; \ 56 if ((n = (hp)->h_q) == 0) \ 57 (hp)->h_q = (m)->m_act = (m); \ 58 else { \ 59 (m)->m_act = n->m_act; \ 60 (hp)->h_q = n->m_act = (m); \ 61 } \ 62 } 63 #define HOST_DEQUE(hp, m) { \ 64 if ((m) = (hp)->h_q) { \ 65 if ((m)->m_act == (m)) \ 66 (hp)->h_q = 0; \ 67 else { \ 68 (m) = (m)->m_act; \ 69 (hp)->h_q->m_act = (m)->m_act; \ 70 } \ 71 (hp)->h_qcnt--; \ 72 (m)->m_act = 0; \ 73 } \ 74 } 75 76 struct hmbuf { 77 int hm_count; /* # of struct's in use */ 78 struct host hm_hosts[HPMBUF]; /* data structures proper */ 79 }; 80 81 #ifdef KERNEL 82 struct host *hostlookup(); 83 struct host *hostenter(); 84 struct mbuf *hostdeque(); 85 #endif 86