[insert project logo here (125x200px max)] Navigator Home Downloads Documentation Research News Forums Project Summary CVS repository Mailinglists Help Announcement Developer Please report any errors or ommissions you find to our `Help' mailinglist, or post a message in the Forums. Copyright and Licensing Information Snap is (c) Jonathan T. Moore, 1999-2002 and licensed under the GNU General Public License (GPL). All other parts of Splash are (c) Willem de Bruijn, 2002-2003 and licensed under the BSD Open Source License. All sourcecode is made publicly available. Acknowledgement Splash and the Splash website are hosted by SourceForge.net

Splash - Documentation SNMP Plus a Lightweight API for SNAP Handling             snap-1.1-wjdb/lib/router.c Go to the documentation of this file. /* snap-1.0. Copyright (C) 2000 by Jonathan T. Moore and Michael Hicks. * * router.c : reads the Linux routing table from /proc/net/route and * implements a simple-minded routing lookup engine. Also, reads * names of interfaces from /proc/net/dev. * * $Id: router.c,v 1.2 2002/12/10 18:51:49 wdebruij Exp $ */ #include <assert.h> /* #include <net/route.h> */ #include <netinet/in.h> #include <net/if.h> #include <string.h> #include "bytecode.h" #include "d_printf.h" #include "memalloc.h" #include "router.h" #include "proc.h" #define NIPQUAD(addr) \ ((unsigned char *)&(addr))[0], \ ((unsigned char *)&(addr))[1], \ ((unsigned char *)&(addr))[2], \ ((unsigned char *)&(addr))[3] static addr_t get_addr(char *addrstr) { char buf[20]; addr_t addr = 0; sprintf(buf,"0x%s",addrstr); sscanf(buf,"%x",&addr); return addr; } static void sprintf_addr(char *addrstr, addr_t addr) { sprintf(addrstr,"%d.%d.%d.%d",NIPQUAD(addr)); } /* MWH---defined my own version of rtentry that uses addr_t's rather than sockaddrs */ struct rtentry { addr_t rt_dst; /* Target address. */ addr_t rt_gateway; /* Gateway addr. */ addr_t rt_genmask; /* Target network mask (IP). */ unsigned short int rt_flags; short int rt_pad2; unsigned long int rt_ifidx; /* index of device used */ unsigned char rt_tos; unsigned char rt_class; short int rt_pad4; short int rt_metric; /* +1 for binary compatibility! */ char *rt_dev; /* Forcing the device at add. */ unsigned long int rt_mtu; /* Per route MTU/Window. */ unsigned long int rt_window; /* Window clamping. */ unsigned short int rt_irtt; /* Initial RTT. */ }; /* route table */ struct rtentry *routes = NULL; int num_rt_entries = 0; int num_routes = 0; /* #define rt_ifidx rt_pad3 */ /* interface table. right now we just track interface names */ char **ifaces = NULL; int num_if_entries = 0; int num_ifaces = 0; /* get the interface number of the named interface */ int get_iface_index(char *iface_name) { int i; assert(iface_name != NULL); for(i = 0; i<num_ifaces; i++) { if (strcmp(iface_name,ifaces[i]) == 0) { return(i); } } return(-1); } /* read interface names in out of /proc/net/dev */ void read_ifaces(char *iface_file) { char buf[2048]; FILE *f; int num_ifs; char **curr_if; char iface[256]; f = fopen(iface_file,"r"); if (f == NULL) { fprintf(stderr,"%s:%d: unable to open %s\n", __FILE__,__LINE__,iface_file); fflush(stderr); exit(1); } num_ifs = 0; /* count number of interfaces */ while(fgets(buf,sizeof(buf),f)) { num_ifs++; } num_ifs -= 2; /* strip off title lines */ d_printf(40,"%s:%d: reading %d interfaces\n",__FILE__,__LINE__,num_ifs); /* make room in the interface table */ if (num_ifs > num_if_entries) { if (ifaces != NULL) { free(ifaces); } memalloc(ifaces,char **,sizeof(char *) * num_ifs); num_if_entries = num_ifs; } /* now read in the interface names */ rewind(f); fgets(buf,sizeof(buf)-1,f); /* strip off 2 title lines */ fgets(buf,sizeof(buf)-1,f); curr_if = &ifaces[0]; while(fgets(buf,sizeof(buf)-1,f)) { int _sscanf_retval = 0; char *cp = NULL; assert(curr_if >= &ifaces[0]); assert(curr_if < &ifaces[num_ifs]); _sscanf_retval = sscanf(buf,"%s",iface); if (_sscanf_retval < 1) { fprintf(stderr, "Warning: scanf (%d) failed on bogus iface entry |%s|\n", _sscanf_retval, buf); continue; } /* strip the : */ cp = &iface[0]; while(*cp != '\0' && *cp != ':') cp++; *cp = '\0'; d_printf(40,"%s:%d: found interface %d = %s\n", __FILE__,__LINE__,(curr_if - ifaces),iface); *curr_if = strdup(iface); curr_if++; } num_ifaces = curr_if - ifaces; return; } /* read routing table out of /proc/net/route */ void read_routes(char *route_file) { char buf[1024]; FILE *f; int nr; struct rtentry *curr_rt; char *fmt; char addrstr1[22],addrstr2[22],addrstr3[22]; char iface[16]; addr_t mask, dest_addr, gw_addr; unsigned int flags,refcnt,use,metric,mtu,window,irtt; f = fopen(route_file,"r"); if (f == NULL) { fprintf(stderr,"%s:%d: unable to open %s\n", __FILE__,__LINE__,route_file); exit(1); } nr = 0; /* count number of routes */ while(fgets(buf,sizeof(buf),f)) { nr++; } nr--; /* strip off title line */ d_printf(40,"%s:%d: reading %d routes\n",__FILE__,__LINE__,nr); /* do we have enough room in the routing table? */ if (nr > num_rt_entries) { if (routes != NULL) { free(routes); } memalloc(routes,struct rtentry *,sizeof(struct rtentry) * nr); num_rt_entries = nr; } /* now read in the routes */ rewind(f); fmt = proc_gen_fmt(route_file, f, "Iface", "%16s", "Destination", "%s", "Gateway", "%s", "Flags", "%X", "RefCnt", "%d", "Use", "%d", "Metric", "%d", "Mask", "%s", "MTU", "%d", "Window", "%d", "IRTT", "%d", NULL); if (fmt == NULL) { fprintf(stderr,"%s:%d: did not get format for reading %s\n",__FILE__, __LINE__,route_file); exit(1); } curr_rt = routes; while(fgets(buf,sizeof(buf)-1,f)) { int ifidx; assert(curr_rt >= &routes[0]); assert(curr_rt < &routes[nr]); if (sscanf(buf,fmt, iface,addrstr1,addrstr2,&flags,&refcnt,&use, &metric,addrstr3,&mtu,&window,&irtt) < 11) { fprintf(stderr,"Warning: scanf failed on bogus tab entry |%s|\n",buf); continue; } /* read the addresses */ dest_addr = get_addr(addrstr1); gw_addr = get_addr(addrstr2); mask = get_addr(addrstr3); ifidx = if_nametoindex(iface); if (ifidx == -1) { /* unknown interface! */ fprintf(stderr,"Warning: unknown iface |%s| in tab entry |%s|\n", iface,buf); continue; } sprintf_addr(addrstr1,dest_addr); sprintf_addr(addrstr2,gw_addr); sprintf_addr(addrstr3,mask); d_printf(45,"%s:%d: route : dst = %s, gw = %s, mask = %s, ifidx = %d (%s)\n", __FILE__,__LINE__,addrstr1,addrstr2,addrstr3, ifidx,iface); curr_rt->rt_ifidx = ifidx; curr_rt->rt_dst = dest_addr; curr_rt->rt_gateway = gw_addr; curr_rt->rt_genmask = mask; curr_rt->rt_flags = (unsigned short int)flags; curr_rt->rt_metric = (short int)metric; curr_rt->rt_mtu = (unsigned long int)mtu; curr_rt->rt_window = (unsigned long int)window; curr_rt->rt_irtt = (unsigned short int)irtt; curr_rt++; } num_routes = curr_rt - routes; } /* looks up the next hop to the given destination address. On success, fill in the results in retval, and return 0. On failure, return -1. */ extern int nexthop(addr_t dstaddr, struct rt_lookup *retval) { int i; assert(retval != NULL); print_anti_timer(16,"nexthop"); for(i=0; i<num_routes; i++) { struct rtentry *rt = &routes[i]; addr_t dest_net = rt->rt_dst; addr_t gw = rt->rt_gateway; addr_t mask = rt->rt_genmask; if ((dstaddr & mask) == dest_net) { print_timer(16,"nexthop"); if (gw == 0) { retval->hopaddr = dstaddr; } else { retval->hopaddr = gw; } retval->ifidx = rt->rt_ifidx; return(0); } } print_timer(16,"nexthop"); return(-1); }