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copied!<p>Here is some code I wrote to find the routes for the machine. I copied the system calls from the code for <code>netstat</code>. Note that I was strongly recommended against doing this, as these system calls are not a supported API and may change at any time. They recommended I just parse the output of <code>netstat</code>.</p> <p>CustomRoute.c:</p> <pre><code>#import "CustomRoute.h" @implementation CustomRoute + (NSMutableArray*) getRoutes { NSMutableArray* routeArray = [NSMutableArray array]; CustomRoute* route = nil; size_t needed; int mib[6]; char *buf, *next, *lim; register struct rt_msghdr2 *rtm; mib[0] = CTL_NET; mib[1] = PF_ROUTE; mib[2] = 0; mib[3] = 0; mib[4] = NET_RT_DUMP2; mib[5] = 0; if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) { err(1, "sysctl: net.route.0.0.dump estimate"); } if ((buf = malloc(needed)) == 0) { err(2, "malloc(%lu)", (unsigned long)needed); } if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { err(1, "sysctl: net.route.0.0.dump"); } lim = buf + needed; for (next = buf; next < lim; next += rtm->rtm_msglen) { rtm = (struct rt_msghdr2 *)next; route = [self getRoute:rtm]; if(route != nil) { [routeArray addObject:route]; } } free(buf); printf("Total routes: %u\n", [routeArray count]); return routeArray; } + (CustomRoute*) getRoute:(struct rt_msghdr2 *)rtm { //sockaddrs are after the message header struct sockaddr* dst_sa = (struct sockaddr *)(rtm + 1); CustomRoute* route = nil; if(rtm->rtm_addrs & RTA_DST) { switch(dst_sa->sa_family) { case AF_INET: if(dst_sa->sa_family == AF_INET && !((rtm->rtm_flags & RTF_WASCLONED) && (rtm->rtm_parentflags & RTF_PRCLONING))) { route = [[CustomRoute alloc] initWithRtm:rtm]; } break; } } return route; } -(void) setAddr:(struct sockaddr*)sa index:(int)rtax_index { if(rtax_index >= 0 && rtax_index < RTAX_MAX) { memcpy(&(m_addrs[rtax_index]), sa, sizeof(struct sockaddr)); } } -(NSString*) getDestination { return [self getAddrStringByIndex:RTAX_DST]; } -(NSString*) getNetmask { return [self getAddrStringByIndex:RTAX_NETMASK]; } -(NSString*) getGateway { return [self getAddrStringByIndex:RTAX_GATEWAY]; } -(NSString*) getDetails { NSMutableString* result = [[NSMutableString alloc] init]; [result appendFormat: [NSString stringWithFormat: @"message type: 0x%06x\n", m_rtm.rtm_type]]; [result appendFormat: [NSString stringWithFormat: @"flags: 0x%06x\n", m_rtm.rtm_flags]]; [result appendFormat: [NSString stringWithFormat: @"addrs: 0x%06x\n", m_rtm.rtm_addrs]]; return result; } -initWithRtm: (struct rt_msghdr2*) rtm { int i; struct sockaddr* sa = (struct sockaddr*)(rtm + 1); //copy over the route message memcpy(&(m_rtm), rtm, sizeof(struct rt_msghdr2)); for(i = 0; i < RTAX_MAX; i++) { [self setAddr:&(sa[i]) index:i]; } return self; } - init { memset(m_addrs, 0, sizeof(m_addrs)); return self; } @end @implementation CustomRoute (Private) -(NSString*) getAddrStringByIndex: (int)rtax_index { NSString * routeString = nil; struct sockaddr* sa = &(m_addrs[rtax_index]); int flagVal = 1 << rtax_index; if(!(m_rtm.rtm_addrs & flagVal)) { return @"none"; } if(rtax_index >= 0 && rtax_index < RTAX_MAX) { switch(sa->sa_family) { case AF_INET: { struct sockaddr_in* si = (struct sockaddr_in *)sa; if(si->sin_addr.s_addr == INADDR_ANY) routeString = @"default"; else routeString = [NSString stringWithCString:(char *)inet_ntoa(si->sin_addr) encoding:NSASCIIStringEncoding]; } break; case AF_LINK: { struct sockaddr_dl* sdl = (struct sockaddr_dl*)sa; if(sdl->sdl_nlen + sdl->sdl_alen + sdl->sdl_slen == 0) { routeString = [NSString stringWithFormat: @"link #%d", sdl->sdl_index]; } else routeString = [NSString stringWithCString:link_ntoa(sdl) encoding:NSASCIIStringEncoding]; } break; default: { char a[3 * sa->sa_len]; char *cp; char *sep = ""; int i; if(sa->sa_len == 0) { routeString = @"empty"; } else { a[0] = (char)NULL; for(i = 0, cp = a; i < sa->sa_len; i++) { cp += sprintf(cp, "%s%02x", sep, (unsigned char)sa->sa_data[i]); sep = ":"; } routeString = [NSString stringWithCString:a encoding:NSASCIIStringEncoding]; } } } } return routeString; } @end </code></pre> <p>CustomRoute.h:</p> <pre><code>#import <Cocoa/Cocoa.h> #import <net/route.h> #import <sys/socket.h> #import <netinet/in.h> #import <net/if_dl.h> #import <sys/sysctl.h> @interface CustomRoute : NSObject { struct sockaddr m_addrs[RTAX_MAX]; struct rt_msghdr2 m_rtm; int m_len; /* length of the sockaddr array */ } + (NSMutableArray*) getRoutes; + (CustomRoute*) getRoute:(struct rt_msghdr2 *)rtm; - (void) setAddr:(struct sockaddr*)sa index:(int)rtax_index; - (NSString*) getDestination; - (NSString*) getNetmask; - (NSString*) getGateway; - initWithRtm: (struct rt_msghdr2*) rtm; @end </code></pre>

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