bootp.c (3436B)
1 #include <u.h> 2 #include <libc.h> 3 #include <ip.h> 4 #include "dat.h" 5 #include "protos.h" 6 7 enum 8 { 9 OfferTimeout= 60, /* when an offer times out */ 10 MaxLease= 60*60, /* longest lease for dynamic binding */ 11 MinLease= 15*60, /* shortest lease for dynamic binding */ 12 StaticLease= 30*60, /* lease for static binding */ 13 14 IPUDPHDRSIZE= 28, /* size of an IP plus UDP header */ 15 MINSUPPORTED= 576, /* biggest IP message the client must support */ 16 17 /* lengths of some bootp fields */ 18 Maxhwlen= 16, 19 Maxfilelen= 128, 20 Maxoptlen= 312-4, 21 22 /* bootp types */ 23 Bootrequest= 1, 24 Bootreply= 2, 25 26 /* bootp flags */ 27 Fbroadcast= 1<<15 28 }; 29 30 typedef struct Hdr Hdr; 31 struct Hdr 32 { 33 uchar op; /* opcode */ 34 uchar htype; /* hardware type */ 35 uchar hlen; /* hardware address len */ 36 uchar hops; /* hops */ 37 uchar xid[4]; /* a random number */ 38 uchar secs[2]; /* elapsed since client started booting */ 39 uchar flags[2]; 40 uchar ciaddr[IPv4addrlen]; /* client IP address (client tells server) */ 41 uchar yiaddr[IPv4addrlen]; /* client IP address (server tells client) */ 42 uchar siaddr[IPv4addrlen]; /* server IP address */ 43 uchar giaddr[IPv4addrlen]; /* gateway IP address */ 44 uchar chaddr[Maxhwlen]; /* client hardware address */ 45 char sname[64]; /* server host name (optional) */ 46 char file[Maxfilelen]; /* boot file name */ 47 uchar optmagic[4]; 48 uchar optdata[Maxoptlen]; 49 }; 50 51 enum 52 { 53 Oca, 54 Osa, 55 Ot 56 }; 57 58 static Field p_fields[] = 59 { 60 {"ca", Fv4ip, Oca, "client IP addr", } , 61 {"sa", Fv4ip, Osa, "server IP addr", } , 62 {0} 63 }; 64 65 #define plan9opt ((ulong)(('p'<<24) | ('9'<<16) | (' '<<8) | ' ')) 66 #define genericopt (0x63825363UL) 67 68 static Mux p_mux[] = 69 { 70 {"dhcp", genericopt,}, 71 {"plan9bootp", plan9opt,}, 72 {"dump", 0,}, 73 {0} 74 }; 75 76 static void 77 p_compile(Filter *f) 78 { 79 Mux *m; 80 81 if(f->op == '='){ 82 compile_cmp(arp.name, f, p_fields); 83 return; 84 } 85 for(m = p_mux; m->name != nil; m++) 86 if(strcmp(f->s, m->name) == 0){ 87 f->pr = m->pr; 88 f->ulv = m->val; 89 f->subop = Ot; 90 return; 91 } 92 sysfatal("unknown bootp field: %s", f->s); 93 } 94 95 static int 96 p_filter(Filter *f, Msg *m) 97 { 98 Hdr *h; 99 100 h = (Hdr*)m->ps; 101 102 if(m->pe < (uchar*)h->sname) 103 return 0; 104 m->ps = h->optdata; 105 106 switch(f->subop){ 107 case Oca: 108 return NetL(h->ciaddr) == f->ulv || NetL(h->yiaddr) == f->ulv; 109 case Osa: 110 return NetL(h->siaddr) == f->ulv; 111 case Ot: 112 return NetL(h->optmagic) == f->ulv; 113 } 114 return 0; 115 } 116 117 static char* 118 op(int i) 119 { 120 static char x[20]; 121 122 switch(i){ 123 case Bootrequest: 124 return "Req"; 125 case Bootreply: 126 return "Rep"; 127 default: 128 sprint(x, "%d", i); 129 return x; 130 } 131 } 132 133 134 static int 135 p_seprint(Msg *m) 136 { 137 Hdr *h; 138 ulong x; 139 140 h = (Hdr*)m->ps; 141 142 if(m->pe < (uchar*)h->sname) 143 return -1; 144 145 /* point past data */ 146 m->ps = h->optdata; 147 148 /* next protocol */ 149 m->pr = nil; 150 if(m->pe >= (uchar*)h->optdata){ 151 x = NetL(h->optmagic); 152 demux(p_mux, x, x, m, &dump); 153 } 154 155 m->p = seprint(m->p, m->e, "t=%s ht=%d hl=%d hp=%d xid=%ux sec=%d fl=%4.4ux ca=%V ya=%V sa=%V ga=%V cha=%E magic=%lux", 156 op(h->op), h->htype, h->hlen, h->hops, 157 NetL(h->xid), NetS(h->secs), NetS(h->flags), 158 h->ciaddr, h->yiaddr, h->siaddr, h->giaddr, h->chaddr, 159 (ulong)NetL(h->optmagic)); 160 if(m->pe > (uchar*)h->sname && *h->sname) 161 m->p = seprint(m->p, m->e, " snam=%s", h->sname); 162 if(m->pe > (uchar*)h->file && *h->file) 163 m->p = seprint(m->p, m->e, " file=%s", h->file); 164 return 0; 165 } 166 167 Proto bootp = 168 { 169 "bootp", 170 p_compile, 171 p_filter, 172 p_seprint, 173 p_mux, 174 "%#.8lux", 175 p_fields, 176 defaultframer 177 };