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RTEMS 4.9.5 On-Line Library


Adding a Default Route

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3.4.5: Adding a Default Route

The function provided in this section is functionally equivalent to the command route add default gw yyy.yyy.yyy.yyy:

void mon_ifconfig(int argc, char *argv[],  unsigned32 command_arg,
                  bool verbose)
{
    struct sockaddr_in  ipaddr;
    struct sockaddr_in  dstaddr;
    struct sockaddr_in  netmask;
    struct sockaddr_in  broadcast;
    char               *iface;
    int                 f_ip        = 0;
    int                 f_ptp       = 0;
    int                 f_netmask   = 0;
    int                 f_up        = 0;
    int                 f_down      = 0;
    int                 f_bcast     = 0;
    int                 cur_idx;
    int                 rc;
    int                 flags;

    bzero((void*) &ipaddr, sizeof(ipaddr));
    bzero((void*) &dstaddr, sizeof(dstaddr));
    bzero((void*) &netmask, sizeof(netmask));
    bzero((void*) &broadcast, sizeof(broadcast));

    ipaddr.sin_len = sizeof(ipaddr);
    ipaddr.sin_family = AF_INET;

    dstaddr.sin_len = sizeof(dstaddr);
    dstaddr.sin_family = AF_INET;

    netmask.sin_len = sizeof(netmask);
    netmask.sin_family = AF_INET;

    broadcast.sin_len = sizeof(broadcast);
    broadcast.sin_family = AF_INET;

    cur_idx = 0;
    if (argc <= 1) {
        /* display all interfaces */
        iface = NULL;
        cur_idx += 1;
    } else {
        iface = argv[1];
        if (isdigit(*argv[2])) {
            if (inet_pton(AF_INET, argv[2], &ipaddr.sin_addr) < 0) {
                printf("bad ip address: %s\n", argv[2]);
                return;
            }
            f_ip = 1;
            cur_idx += 3;
        } else {
            cur_idx += 2;
        }
    }

    if ((f_down !=0) && (f_ip != 0)) {
        f_up = 1;
    }

    while(argc > cur_idx) {
        if (strcmp(argv[cur_idx], "up") == 0) {
            f_up = 1;
            if (f_down != 0) {
                printf("Can't make interface up and down\n");
            }
        } else if(strcmp(argv[cur_idx], "down") == 0) {
            f_down = 1;
            if (f_up != 0) {
                printf("Can't make interface up and down\n");
            }
        } else if(strcmp(argv[cur_idx], "netmask") == 0) {
            if ((cur_idx + 1) >= argc) {
                printf("No netmask address\n");
                return;
            }
            if (inet_pton(AF_INET, argv[cur_idx+1], &netmask.sin_addr) < 0) {
                printf("bad netmask: %s\n", argv[cur_idx]);
                return;
            }
            f_netmask = 1;
            cur_idx += 1;
        } else if(strcmp(argv[cur_idx], "broadcast") == 0) {
            if ((cur_idx + 1) >= argc) {
                printf("No broadcast address\n");
                return;
            }
            if (inet_pton(AF_INET, argv[cur_idx+1], &broadcast.sin_addr) < 0) {
                printf("bad broadcast: %s\n", argv[cur_idx]);
                return;
            }
            f_bcast = 1;
            cur_idx += 1;
        } else if(strcmp(argv[cur_idx], "pointopoint") == 0) {
            if ((cur_idx + 1) >= argc) {
                printf("No pointopoint address\n");
                return;
            }
            if (inet_pton(AF_INET, argv[cur_idx+1], &dstaddr.sin_addr) < 0) {
                printf("bad pointopoint: %s\n", argv[cur_idx]);
                return;
            }

            f_ptp = 1;
            cur_idx += 1;
        } else {
            printf("Bad parameter: %s\n", argv[cur_idx]);
            return;
        }

        cur_idx += 1;
    }

    printf("ifconfig ");
    if (iface != NULL) {
        printf("%s ", iface);
        if (f_ip != 0) {
            char str[256];
            inet_ntop(AF_INET, &ipaddr.sin_addr, str, 256);
            printf("%s ", str);
        }

        if (f_netmask != 0) {
            char str[256];
            inet_ntop(AF_INET, &netmask.sin_addr, str, 256);
            printf("netmask %s ", str);
        }

        if (f_bcast != 0) {
            char str[256];
            inet_ntop(AF_INET, &broadcast.sin_addr, str, 256);
            printf("broadcast %s ", str);
        }

        if (f_ptp != 0) {
            char str[256];
            inet_ntop(AF_INET, &dstaddr.sin_addr, str, 256);
            printf("pointopoint %s ", str);
        }

        if (f_up != 0) {
            printf("up\n");
        } else if (f_down != 0) {
            printf("down\n");
        } else {
            printf("\n");
        }
    }

    if ((iface == NULL) || ((f_ip == 0) && (f_down == 0) && (f_up == 0))) {
        rtems_bsdnet_show_if_stats();
        return;
    }

    flags = 0;
    if (f_netmask) {
        rc = rtems_bsdnet_ifconfig(iface, SIOCSIFNETMASK, &netmask);
        if (rc < 0) {
            printf("Could not set netmask: %s\n", strerror(errno));
            return;
        }
    }

    if (f_bcast) {
        rc = rtems_bsdnet_ifconfig(iface, SIOCSIFBRDADDR, &broadcast);
        if (rc < 0) {
            printf("Could not set broadcast: %s\n", strerror(errno));
            return;
        }
    }

    if (f_ptp) {
        rc = rtems_bsdnet_ifconfig(iface, SIOCSIFDSTADDR, &dstaddr);
        if (rc < 0) {
            printf("Could not set destination address: %s\n", strerror(errno));
            return;
        }
        flags |= IFF_POINTOPOINT;
    }

    /* This must come _after_ setting the netmask, broadcast addresses */
    if (f_ip) {
        rc = rtems_bsdnet_ifconfig(iface, SIOCSIFADDR, &ipaddr);
        if (rc < 0) {
            printf("Could not set IP address: %s\n", strerror(errno));
            return;
        }
    }

    if (f_up != 0) {
        flags |= IFF_UP;
    }

    if (f_down != 0) {
        printf("Warning: taking interfaces down is not supported\n");
    }

    rc = rtems_bsdnet_ifconfig(iface, SIOCSIFFLAGS, &flags);
    if (rc < 0) {
        printf("Could not set interface flags: %s\n", strerror(errno));
        return;
    }
}



void mon_route(int argc, char *argv[],  unsigned32 command_arg,
               bool verbose)
{
    int                cmd;
    struct sockaddr_in dst;
    struct sockaddr_in gw;
    struct sockaddr_in netmask;
    int                f_host;
    int                f_gw       = 0;
    int                cur_idx;
    int                flags;
    int                rc;

    memset(&dst, 0, sizeof(dst));
    memset(&gw, 0, sizeof(gw));
    memset(&netmask, 0, sizeof(netmask));

    dst.sin_len = sizeof(dst);
    dst.sin_family = AF_INET;
    dst.sin_addr.s_addr = inet_addr("0.0.0.0");

    gw.sin_len = sizeof(gw);
    gw.sin_family = AF_INET;
    gw.sin_addr.s_addr = inet_addr("0.0.0.0");

    netmask.sin_len = sizeof(netmask);
    netmask.sin_family = AF_INET;
    netmask.sin_addr.s_addr = inet_addr("255.255.255.0");

    if (argc < 2) {
        rtems_bsdnet_show_inet_routes();
        return;
    }

    if (strcmp(argv[1], "add") == 0) {
        cmd = RTM_ADD;
    } else if (strcmp(argv[1], "del") == 0) {
        cmd = RTM_DELETE;
    } else {
        printf("invalid command: %s\n", argv[1]);
        printf("\tit should be 'add' or 'del'\n");
        return;
    }

    if (argc < 3) {
        printf("not enough arguments\n");
        return;
    }

    if (strcmp(argv[2], "-host") == 0) {
        f_host = 1;
    } else if (strcmp(argv[2], "-net") == 0) {
        f_host = 0;
    } else {
        printf("Invalid type: %s\n", argv[1]);
        printf("\tit should be '-host' or '-net'\n");
        return;
    }

    if (argc < 4) {
        printf("not enough arguments\n");
        return;
    }

    inet_pton(AF_INET, argv[3], &dst.sin_addr);

    cur_idx = 4;
    while(cur_idx < argc) {
        if (strcmp(argv[cur_idx], "gw") == 0) {
            if ((cur_idx +1) >= argc) {
                printf("no gateway address\n");
                return;
            }
            f_gw = 1;
            inet_pton(AF_INET, argv[cur_idx + 1], &gw.sin_addr);
            cur_idx += 1;
        } else if(strcmp(argv[cur_idx], "netmask") == 0) {
            if ((cur_idx +1) >= argc) {
                printf("no netmask address\n");
                return;
            }
            f_gw = 1;
            inet_pton(AF_INET, argv[cur_idx + 1], &netmask.sin_addr);
            cur_idx += 1;
        } else {
            printf("Unknown argument\n");
            return;
        }
        cur_idx += 1;
    }

    flags = RTF_STATIC;
    if (f_gw != 0) {
        flags |= RTF_GATEWAY;
    }
    if (f_host != 0) {
        flags |= RTF_HOST;
    }

    rc = rtems_bsdnet_rtrequest(cmd, &dst, &gw, &netmask, flags, NULL);
    if (rc < 0) {
        printf("Error adding route\n");
    }
}

Thanks to Jay Monkman for this example code.


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