changeset 961:d80750c9321f

netstat by Ranjan Kumar.
author Rob Landley <rob@landley.net>
date Thu, 25 Jul 2013 13:30:58 -0500
parents c0627c163893
children 194acfd68755
files toys/pending/netstat.c
diffstat 1 files changed, 658 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/pending/netstat.c	Thu Jul 25 13:30:58 2013 -0500
@@ -0,0 +1,658 @@
+/* netstat.c - Display Linux networking subsystem.
+ *
+ * Copyright 2012 Ranjan Kumar <ranjankumar.bth@gmail.com>
+ *
+ * Not in SUSv4.
+ *
+USE_NETSTAT(NEWTOY(netstat, "pWrxwutneal", TOYFLAG_BIN))
+config NETSTAT
+  bool "netstat"
+  default n
+  help
+    usage: netstat [-pWrxwutneal]
+
+    Display networking information.
+
+    -r  Display routing table.
+    -a  Display all sockets (Default: Connected).
+    -l  Display listening server sockets.
+    -t  Display TCP sockets.
+    -u  Display UDP sockets.
+    -w  Display Raw sockets.
+    -x  Display Unix sockets.
+    -e  Display other/more information.
+    -n  Don't resolve names.
+    -W  Wide Display.
+    -p  Display PID/Program name for sockets.
+*/
+
+#define FOR_netstat
+#include "toys.h"
+#include "toynet.h"
+#include <net/route.h>
+
+typedef union _iaddr {
+  unsigned u;
+  unsigned char b[4];
+} iaddr;
+
+typedef union _iaddr6 {
+  struct {
+    unsigned a;
+    unsigned b;
+    unsigned c;
+    unsigned d;
+  } u;
+  unsigned char b[16];
+} iaddr6;
+
+#define ADDR_LEN (INET6_ADDRSTRLEN + 1 + 5 + 1) //IPv6 addr len + : + port + '\0'
+
+//For unix states
+enum {
+	SOCK_ACCEPTCON = (1 << 16),  //performed a listen.
+	SOCK_WAIT_DATA = (1 << 17),  //wait data to read.
+	SOCK_NO_SPACE = (1 << 18),  //no space to write.
+};
+
+#define SOCK_NOT_CONNECTED 1
+//For PID/Progrma Name
+#define PROGRAM_NAME "PID/Program Name"
+#define PROGNAME_LEN 21
+
+typedef struct _pidlist {
+  struct _pidlist *next;
+  long inode;
+  char name[PROGNAME_LEN];
+} PID_LIST;
+PID_LIST *pid_list = NULL;
+
+/*
+ * Get base name from the input name.
+ */
+static const char *get_basename(char *name)
+{
+  const char *c = strrchr(name, '/');
+  if (c) return c + 1;
+  return name;
+}
+/*
+ * copy string from src to dest -> only number of bytes.
+ */
+static char *safe_strncpy(char *dst, char *src, size_t size)
+{
+  if(!size) return dst;
+  dst[--size] = '\0';
+  return strncpy(dst, src, size);
+}
+
+/*
+ * locate character in string.
+ */
+static char *strchr_nul(char *s, int c)
+{
+  while(*s != '\0' && *s != c) s++;
+  return (char*)s;
+}
+
+// Find out if the last character of a string matches with the given one.
+// Don't underrun the buffer if the string length is 0.
+static char *find_last_char(char *str, int c)
+{
+  if (str && *str) {
+    size_t sz = strlen(str) - 1;
+    str += sz;
+    if ( (unsigned char)*str == c) return (char*)str;
+  }
+  return NULL;
+}
+/*
+ * Concat path and the file name.
+ */
+static char *append_pathandfile(char *path, char *fname)
+{
+  char *c;
+  if (!path) path = "";
+  c = find_last_char(path, '/');
+  while (*fname == '/') fname++;
+  return xmsprintf("%s%s%s", path, (c)? "" : "/", fname);
+}
+/*
+ * Concat sub-path and the file name.
+ */
+static char *append_subpathandfile(char *path, char *fname)
+{
+#define ISDOTORDOTDOT(s) ((s)[0] == '.' && (!(s)[1] || ((s)[1] == '.' && !(s)[2])))
+  if(!fname) return NULL;
+  if(ISDOTORDOTDOT(fname)) return NULL;
+  return append_pathandfile(path, fname);
+#undef ISDOTORDOTDOT
+}
+/*
+ * used to converts string into int and validate the input str for invalid int value or out-of-range.
+ */
+static unsigned get_strtou(char *str, char **endp, int base)
+{
+  unsigned long uli;
+  char *endptr;
+
+  if (!isalnum(str[0])) {
+    errno = ERANGE;
+    return UINT_MAX;
+  }
+  errno = 0;
+  uli = strtoul(str, &endptr, base);
+  if (uli > UINT_MAX) {
+    errno = ERANGE;
+    return UINT_MAX;
+  }
+
+  if (endp) *endp = endptr;
+  if (endptr[0]) {
+    if (isalnum(endptr[0]) || errno) { //"123abc" or out-of-range
+      errno = ERANGE;
+      return UINT_MAX;
+    }
+    errno = EINVAL;
+  }
+  return uli;
+}
+/*
+ * used to retrive pid name from pid list.
+ */
+static const char *get_pid_name(unsigned long inode)
+{
+  PID_LIST *tmp;
+  for (tmp = pid_list; tmp; tmp = tmp->next)
+    if (tmp->inode == inode) return tmp->name;
+  return "-";
+}
+/*
+ * For TCP/UDP/RAW display data.
+ */
+static void display_data(unsigned rport, char *label, unsigned rxq, unsigned txq, char *lip, char *rip, unsigned state, unsigned long inode)
+{
+  char *ss_state = "UNKNOWN";
+  char *state_label[] = {"", "ESTABLISHED", "SYN_SENT", "SYN_RECV", "FIN_WAIT1", "FIN_WAIT2",
+  		                 "TIME_WAIT", "CLOSE", "CLOSE_WAIT", "LAST_ACK", "LISTEN", "CLOSING", "UNKNOWN"};
+  if (!strcmp(label, "tcp")) {
+    int sz = ARRAY_LEN(state_label);
+    if (!state || state >= sz) state = sz-1;
+    ss_state = state_label[state];
+  }
+  else if (!strcmp(label, "udp")) {
+    if (state == 1) ss_state = state_label[state];
+    else if (state == 7) ss_state = "";
+  }
+  else if (!strcmp(label, "raw")) ss_state = itoa(state);
+
+  if ( (toys.optflags & FLAG_W) && (toys.optflags & FLAG_p))
+    xprintf("%3s   %6d %6d %-51s %-51s %-12s%s\n", label, rxq, txq, lip, rip, ss_state, get_pid_name(inode));
+  else if (toys.optflags & FLAG_W)
+    xprintf("%3s   %6d %6d %-51s %-51s %-12s\n", label, rxq, txq, lip, rip, ss_state);
+  else if (toys.optflags & FLAG_p)
+    xprintf("%3s   %6d %6d %-23s %-23s %-12s%s\n", label, rxq, txq, lip, rip, ss_state, get_pid_name(inode));
+  else xprintf("%3s   %6d %6d %-23s %-23s %-12s\n", label, rxq, txq, lip, rip, ss_state);
+}
+/*
+ * For TCP/UDP/RAW show data.
+ */
+static void show_data(unsigned rport, char *label, unsigned rxq, unsigned txq, char *lip, char *rip, unsigned state, unsigned long inode)
+{
+  if (toys.optflags & FLAG_l) {
+    if (!rport && (state && 0xA)) display_data(rport, label, rxq, txq, lip, rip, state, inode);
+  } else if (toys.optflags & FLAG_a) display_data(rport, label, rxq, txq, lip, rip, state, inode);
+  //rport && (TCP | UDP | RAW)
+  else if (rport && (0x10 | 0x20 | 0x40)) display_data(rport, label, rxq, txq, lip, rip, state, inode);
+}
+/*
+ * used to get service name.
+ */
+static char *get_servname(int port, char *label)
+{
+  int lport = htons(port);
+  if (!lport) return xmsprintf("%s", "*");
+  struct servent *ser = getservbyport(lport, label);
+  if (ser) return xmsprintf("%s", ser->s_name);
+  return xmsprintf("%s", itoa(ntohs(lport)));
+}
+/*
+ * used to convert address into text format.
+ */
+static void addr2str(int af, void *addr, unsigned port, char *buf, char *label)
+{
+  char ip[ADDR_LEN] = {0,};
+  if (!inet_ntop(af, addr, ip, ADDR_LEN)) {
+    *buf = '\0';
+    return;
+  }
+  size_t iplen = strlen(ip);
+  if (!port) {
+    strncat(ip+iplen, ":*", ADDR_LEN-iplen-1);
+    memcpy(buf, ip, ADDR_LEN);
+    return;
+  }
+
+  if (!(toys.optflags & FLAG_n)) {
+    struct addrinfo hints, *result, *rp;
+
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = af;
+
+    if (!getaddrinfo(ip, NULL, &hints, &result)) {
+      char hbuf[NI_MAXHOST] = {0,}, sbuf[NI_MAXSERV] = {0,};
+      socklen_t sock_len;
+      char *sname = NULL;
+      int plen = 0;
+
+      if (af == AF_INET) sock_len = sizeof(struct sockaddr_in);
+      else sock_len = sizeof(struct sockaddr_in6);
+
+      for (rp = result; rp; rp = rp->ai_next)
+        if (!getnameinfo(rp->ai_addr, sock_len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf), NI_NUMERICSERV))
+          break;
+
+      freeaddrinfo(result);
+      sname = get_servname(port, label);
+      plen = strlen(sname);
+      if (*hbuf) {
+        memset(ip, 0, ADDR_LEN);
+        memcpy(ip, hbuf, (ADDR_LEN - plen - 2));
+        iplen = strlen(ip);
+      }
+      snprintf(ip + iplen, ADDR_LEN-iplen, ":%s", sname);
+      free(sname);
+    }
+  }
+  else snprintf(ip+iplen, ADDR_LEN-iplen, ":%d", port);
+  memcpy(buf, ip, ADDR_LEN);
+}
+/*
+ * display ipv4 info for TCP/UDP/RAW.
+ */
+static void show_ipv4(char *fname, char *label)
+{
+  FILE *fp = fopen((char *)fname, "r");
+  if (!fp) {
+     perror_msg("'%s'", fname);
+     return;
+  }
+  fgets(toybuf, sizeof(toybuf), fp); //skip header.
+  while (fgets(toybuf, sizeof(toybuf), fp)) {
+    char lip[ADDR_LEN] = {0,}, rip[ADDR_LEN] = {0,};
+    iaddr laddr, raddr;
+    unsigned lport, rport, state, txq, rxq, num, uid;
+    unsigned long inode;
+
+    int nitems = sscanf(toybuf, " %d: %x:%x %x:%x %x %x:%x %*X:%*X %*X %d %*d %ld",
+        &num, &laddr.u, &lport, &raddr.u, &rport, &state, &txq, &rxq, &uid, &inode);
+    if (nitems == 10) {
+      addr2str(AF_INET, &laddr, lport, lip, label);
+      addr2str(AF_INET, &raddr, rport, rip, label);
+      show_data(rport, label, rxq, txq, lip, rip, state, inode);
+    }
+  }//End of While
+  fclose(fp);
+}
+/*
+ * display ipv6 info for TCP/UDP/RAW.
+ */
+static void show_ipv6(char *fname, char *label)
+{
+  FILE *fp = fopen((char *)fname, "r");
+  if (!fp) {
+    perror_msg("'%s'", fname);
+    return;
+  }
+  fgets(toybuf, sizeof(toybuf), fp); //skip header.
+  while (fgets(toybuf, sizeof(toybuf), fp)) {
+    char lip[ADDR_LEN] = {0,}, rip[ADDR_LEN] = {0,};
+    iaddr6 laddr6, raddr6;
+    unsigned lport, rport, state, txq, rxq, num, uid;
+    unsigned long inode;
+    int nitems = sscanf(toybuf, " %d: %8x%8x%8x%8x:%x %8x%8x%8x%8x:%x %x %x:%x %*X:%*X %*X %d %*d %ld",
+        &num, &laddr6.u.a, &laddr6.u.b, &laddr6.u.c, &laddr6.u.d, &lport, &raddr6.u.a, &raddr6.u.b,
+        &raddr6.u.c, &raddr6.u.d, &rport, &state, &txq, &rxq, &uid, &inode);
+    if (nitems == 16) {
+      addr2str(AF_INET6, &laddr6, lport, lip, label);
+      addr2str(AF_INET6, &raddr6, rport, rip, label);
+      show_data(rport, label, rxq, txq, lip, rip, state, inode);
+    }
+  }//End of While
+  fclose(fp);
+}
+/*
+ * display unix socket info.
+ */
+static void show_unix_sockets(char *fname, char *label)
+{
+  FILE *fp = fopen((char *)fname, "r");
+  if (!fp) {
+    perror_msg("'%s'", fname);
+    return;
+  }
+  fgets(toybuf, sizeof(toybuf), fp); //skip header.
+  while (fgets(toybuf, sizeof(toybuf), fp)) {
+    unsigned long int refcount, label, flags, inode;
+    int nitems = 0, path_offset = 0, type, state;
+    char sock_flags[32] = {0,}, *sock_type, *sock_state, *bptr = toybuf;
+
+    if (!toybuf[0]) continue;
+    nitems = sscanf(toybuf, "%*p: %lX %lX %lX %X %X %lu %n",
+        &refcount, &label, &flags, &type, &state, &inode, &path_offset);
+    //for state one less
+    if (nitems < 6) break;
+    if (toys.optflags & FLAG_l) {
+      if ( !((state == SOCK_NOT_CONNECTED) && (flags & SOCK_ACCEPTCON)) ) continue;
+    } else if (!(toys.optflags & FLAG_a)) {
+      if ((state == SOCK_NOT_CONNECTED) && (flags & SOCK_ACCEPTCON)) continue;
+    }
+
+    //prepare socket type, state and flags.
+    {
+      char *ss_type[] = { "", "STREAM", "DGRAM", "RAW", "RDM", "SEQPACKET", "UNKNOWN"};
+      char *ss_state[] = { "FREE", "LISTENING", "CONNECTING", "CONNECTED", "DISCONNECTING", "UNKNOWN"};
+
+      int sz = ARRAY_LEN(ss_type);//sizeof(ss_type)/sizeof(ss_type[0]);
+      if ( (type < SOCK_STREAM) || (type > SOCK_SEQPACKET) ) sock_type = ss_type[sz-1];
+      else sock_type = ss_type[type];
+
+      sz = ARRAY_LEN(ss_state);//sizeof(ss_state)/sizeof(ss_state[0]);
+      if ((state < 0) || (state > sz-2)) sock_state = ss_state[sz-1];
+      else if (state == SOCK_NOT_CONNECTED) {
+        if (flags & SOCK_ACCEPTCON) sock_state = ss_state[state];
+        else sock_state = " ";
+      } else sock_state = ss_state[state];
+
+      strcpy(sock_flags, "[ ");
+      if (flags & SOCK_ACCEPTCON) strcat(sock_flags, "ACC ");
+      if (flags & SOCK_WAIT_DATA) strcat(sock_flags, "W ");
+      if (flags & SOCK_NO_SPACE) strcat(sock_flags, "N ");
+      strcat(sock_flags, "]");
+    }
+    xprintf("%-5s %-6ld %-11s %-10s %-13s %6lu ", (!label ? "unix" : "??"), refcount, sock_flags, sock_type, sock_state, inode);
+    if (toys.optflags & FLAG_p) xprintf("%-20s", get_pid_name(inode));
+
+    bptr += path_offset;
+    *strchr_nul(bptr, '\n') = '\0';
+    xprintf("%s\n", bptr);
+  }//End of while
+  fclose(fp);
+}
+/*
+ * extract inode value from the link.
+ */
+static long ss_inode(char *link)
+{
+  long inode = -1;
+  //"link = socket:[12345]", get "12345" as inode.
+  if (!strncmp(link, "socket:[", sizeof("socket:[")-1)) {
+    inode = get_strtou(link + sizeof("socket:[")-1, (char**)&link, 0);
+    if (*link != ']') inode = -1;
+  }
+  //"link = [0000]:12345", get "12345" as inode.
+  else if (!strncmp(link, "[0000]:", sizeof("[0000]:")-1)) {
+    inode = get_strtou(link + sizeof("[0000]:")-1, NULL, 0);
+    //if not NULL terminated.
+    if (errno) inode = -1;
+  }
+  return inode;
+}
+/*
+ * add inode and progname in the pid list.
+ */
+static void add2list(long inode, char *progname)
+{
+  PID_LIST *node = pid_list;
+  for(; node; node = node->next) {
+    if(node->inode == inode)
+      return;
+  }
+  PID_LIST *new = (PID_LIST *)xzalloc(sizeof(PID_LIST));
+  new->inode = inode;
+  safe_strncpy(new->name, progname, PROGNAME_LEN-1);
+  new->next = pid_list;
+  pid_list = new;
+}
+/*
+ * add pid info in the list.
+ */
+static void extract_inode(char *path, char *progname)
+{
+  DIR *dp;
+  struct dirent *entry;
+
+  if (!(dp = opendir(path))) {
+    if (errno == EACCES) return;
+    else perror_exit("%s", path);
+  }
+  while ((entry = readdir(dp))) {
+    char *link = NULL, *fname = append_subpathandfile(path, entry->d_name);
+    if (!fname) continue;
+    link = xreadlink(fname);
+    if (link) {
+      long inode = ss_inode(link);
+      free(link);
+      if (inode != -1) add2list(inode, progname);
+    }
+    free(fname);
+  }//end of while.
+  closedir(dp);
+}
+/*
+ * prepare the list for all pids in /proc directory.
+ */
+static void get_pid_list(void)
+{
+  DIR *dp;
+  struct dirent *entry;
+  char path[64] = {0,};
+  uid_t uid = geteuid();
+
+  if (!(dp = opendir("/proc"))) perror_exit("opendir");
+
+  while ((entry = readdir(dp))) {
+    int fd, nitems = 0, length = 0;
+    char *pid, *progname;
+
+    if (!isdigit(*entry->d_name)) continue;
+    pid = entry->d_name;
+    length = snprintf(path, sizeof(path), "/proc/%s/cmdline", entry->d_name);
+    if (sizeof(path) <= length) continue;
+
+    fd = xopen(path, O_RDONLY);
+    nitems = readall(fd, toybuf, sizeof(toybuf) - 1);
+    xclose(fd);
+    if (nitems < 1) continue;
+    toybuf[nitems] = '\0';
+    strcpy(path + length - (sizeof("cmdline")-1), "fd");
+    progname = append_pathandfile(pid, (char *)get_basename(toybuf)); //e.g. progname = 2054/gnome-keyring-daemon
+    extract_inode(path, progname);
+  }//end of while.
+  closedir(dp);
+
+  if (uid) fprintf(stderr, "(Not all processes could be identified, non-owned process info "
+      "will not be shown, you would have to be root to see it all.)\n");
+}
+/*
+ * Dealloc pid list.
+ */
+static void clean_pid_list(void)
+{
+  PID_LIST *tmp;
+  while (pid_list) {
+    tmp = pid_list->next;
+    free(pid_list);
+    pid_list = tmp;
+  }
+}
+/*
+ * For TCP/UDP/RAW show the header.
+ */
+static void show_header(void)
+{
+  if ((toys.optflags & FLAG_W) && (toys.optflags & FLAG_p))
+    xprintf("\nProto Recv-Q Send-Q %-51s %-51s %-12s%s\n", "Local Address", "Foreign Address", "State", PROGRAM_NAME);
+  else if (toys.optflags & FLAG_p)
+    xprintf("\nProto Recv-Q Send-Q %-23s %-23s %-12s%s\n", "Local Address", "Foreign Address", "State", PROGRAM_NAME);
+  else if (toys.optflags & FLAG_W)
+	  xprintf("\nProto Recv-Q Send-Q %-51s %-51s State     \n", "Local Address", "Foreign Address");
+  else xprintf("\nProto Recv-Q Send-Q %-23s %-23s State     \n", "Local Address", "Foreign Address");
+}
+/*
+ * used to get the flag values for route command.
+ */
+static void get_flag_value(char **flagstr, int flags)
+{
+  int i = 0;
+  char *str = *flagstr;
+  static const char flagchars[] = "GHRDMDAC";
+  static const unsigned flagarray[] = {
+    RTF_GATEWAY,
+    RTF_HOST,
+    RTF_REINSTATE,
+    RTF_DYNAMIC,
+    RTF_MODIFIED,
+    RTF_DEFAULT,
+    RTF_ADDRCONF,
+    RTF_CACHE
+  };
+  *str++ = 'U';
+  while ( (*str = flagchars[i]) ) {
+    if (flags & flagarray[i++]) ++str;
+  }
+}
+/*
+ * extract inet4 route info from /proc/net/route file and display it.
+ */
+static void display_routes(int is_more_info, int notresolve)
+{
+#define IPV4_MASK (RTF_GATEWAY|RTF_HOST|RTF_REINSTATE|RTF_DYNAMIC|RTF_MODIFIED)
+  unsigned long dest, gate, mask;
+  int flags, ref, use, metric, mss, win, irtt;
+  char iface[64]={0,};
+  char *flag_val = xzalloc(10); //there are 9 flags "UGHRDMDAC" for route.
+
+  FILE *fp = xfopen("/proc/net/route", "r");
+  xprintf("Kernel IP routing table\n"
+                   "Destination     Gateway         Genmask         Flags %s Iface\n",
+  	                        is_more_info ? "  MSS Window  irtt" : "Metric Ref    Use");
+  fgets(toybuf, sizeof(toybuf), fp); //skip 1st line.
+  while (fgets(toybuf, sizeof(toybuf), fp)) {
+     int nitems = 0;
+     char *destip = NULL, *gateip = NULL, *maskip = NULL;
+     memset(flag_val, 0, 10);
+
+     nitems = sscanf(toybuf, "%63s%lx%lx%X%d%d%d%lx%d%d%d\n",
+                 iface, &dest, &gate, &flags, &ref, &use, &metric, &mask, &mss, &win, &irtt);
+     if (nitems != 11) {//EOF with no (nonspace) chars read.
+       if ((nitems < 0) && feof(fp)) break;
+      perror_exit("sscanf");
+    }
+    //skip down interfaces.
+    if (!(flags & RTF_UP)) continue;
+
+    if (dest) {//For Destination
+      if (inet_ntop(AF_INET, &dest, toybuf, sizeof(toybuf)) ) destip = xstrdup(toybuf);
+    } else {
+      if (!notresolve) destip = xstrdup("default");
+      else destip = xstrdup("0.0.0.0");
+    }
+    if (gate) {//For Gateway
+      if (inet_ntop(AF_INET, &gate, toybuf, sizeof(toybuf)) ) gateip = xstrdup(toybuf);
+    } else {
+      if (!notresolve) gateip = xstrdup("*");
+      else gateip = xstrdup("0.0.0.0");
+    }
+    //For Mask
+    if (inet_ntop(AF_INET, &mask, toybuf, sizeof(toybuf)) ) maskip = xstrdup(toybuf);
+
+    //Get flag Values
+    get_flag_value(&flag_val, (flags & IPV4_MASK));
+    if (flags & RTF_REJECT) flag_val[0] = '!';
+    xprintf("%-15.15s %-15.15s %-16s%-6s", destip, gateip, maskip, flag_val);
+    if (destip) free(destip);
+    if (gateip) free(gateip);
+    if (maskip) free(maskip);
+    if (is_more_info) xprintf("%5d %-5d %6d %s\n", mss, win, irtt, iface);
+    else xprintf("%-6d %-2d %7d %s\n", metric, ref, use, iface);
+  }//end of while.
+  fclose(fp);
+  if (flag_val) free(flag_val);
+#undef IPV4_MASK
+  return;
+}
+/*
+ * netstat utily main function.
+ */
+void netstat_main(void)
+{
+#define IS_NETSTAT_PROTO_FLAGS_UP (toys.optflags & (FLAG_t | FLAG_u | FLAG_w | FLAG_x))
+  int flag_listen_and_all = 0;
+  if (!toys.optflags) toys.optflags = FLAG_t | FLAG_u | FLAG_w | FLAG_x;
+
+  //When a is set
+  if (toys.optflags & FLAG_a) flag_listen_and_all = 1;
+  //when a and l both are set
+  if ( (toys.optflags & FLAG_a) && (toys.optflags & FLAG_l) )
+    toys.optflags &= ~FLAG_l;
+  //when only a is set
+  if ( (toys.optflags & FLAG_a) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
+    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
+  //when only l is set
+  if ( (toys.optflags & FLAG_l) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
+    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
+  //when only e/n is set
+  if( ((toys.optflags & FLAG_e) || (toys.optflags & FLAG_n)) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
+	  toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
+  //when W is set
+  if ( (toys.optflags & FLAG_W) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
+    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
+   //when p is set
+  if ( (toys.optflags & FLAG_p) && (!IS_NETSTAT_PROTO_FLAGS_UP) )
+    toys.optflags |= FLAG_t | FLAG_u | FLAG_w | FLAG_x;
+
+  //Display routing table.
+  if (toys.optflags & FLAG_r) {
+    display_routes(!(toys.optflags & FLAG_e), (toys.optflags & FLAG_n));
+    return;
+  }
+
+  if (toys.optflags & FLAG_p) get_pid_list();
+
+  //For TCP/UDP/RAW.
+  if ( (toys.optflags & FLAG_t) || (toys.optflags & FLAG_u) || (toys.optflags & FLAG_w) ) {
+    xprintf("Active Internet connections ");
+
+    if (flag_listen_and_all) xprintf("(servers and established)");
+    else if (toys.optflags & FLAG_l) xprintf("(only servers)");
+    else xprintf("(w/o servers)");
+
+    show_header();
+    if (toys.optflags & FLAG_t) {//For TCP
+      show_ipv4("/proc/net/tcp",  "tcp");
+      show_ipv6("/proc/net/tcp6", "tcp");
+    }
+    if (toys.optflags & FLAG_u) {//For UDP
+      show_ipv4("/proc/net/udp",  "udp");
+      show_ipv6("/proc/net/udp6", "udp");
+    }
+    if (toys.optflags & FLAG_w) {//For raw
+      show_ipv4("/proc/net/raw",  "raw");
+      show_ipv6("/proc/net/raw6", "raw");
+    }
+  }
+  if (toys.optflags & FLAG_x) {//For UNIX.
+    xprintf("Active UNIX domain sockets ");
+    if (flag_listen_and_all) xprintf("(servers and established)");
+    else if (toys.optflags & FLAG_l) xprintf("(only servers)");
+    else xprintf("(w/o servers)");
+
+    if (toys.optflags & FLAG_p) xprintf("\nProto RefCnt Flags       Type       State         I-Node %s    Path\n", PROGRAM_NAME);
+    else xprintf("\nProto RefCnt Flags       Type       State         I-Node Path\n");
+    show_unix_sockets("/proc/net/unix", "unix");
+  }
+  if (toys.optflags & FLAG_p) clean_pid_list();
+  if (toys.exitval) toys.exitval = 0;
+#undef IS_NETSTAT_PROTO_FLAGS_UP
+}