sockstat: don't use getprotoent(3)

This removes requirement for existence of obsolete IPPROTO_DIVERT in
<netinet/in.h> and the 'divert' entry in /etc/protocols.

Also, this avoids running through the nsdispatch(3) machinery on startup,
cutting down about 20 syscalls, three of which are open(2).  The code of
sockstat(1) itself is also reduced.

The only UI change for a normal execution is that now the divert(4)
sockets are reported as "divert4" instead of "div4".  The prefix "4"
itself is also incorrect, as divert(4) is not a part of IPv4.  This will
be addressed in a separate change.

There is small UI change for incorrect runs.  Previously protocols listed
in /etc/protocols, but not supported, would err out like this:

  # sockstat -P ggp
  sockstat: protocol 3 not supported

And non-existent protocols would err out like this:

  # sockstat -P foo
  sockstat: cap_getprotobyname: No error: 0 USER COMMAND
  PID FD PROTO LOCAL ADDRESS         FOREIGN ADDRESS

Now both cases will consistently err:

  sockstat: protocol foo not supported

Reviewed by:		pouria, tuexen
Differential Revision:	https://reviews.freebsd.org/D57507

usr.bin/sockstat/main.c

@@ -58,7 +58,6 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <jail.h>
-#include <netdb.h>
 #include <pwd.h>
 #include <stdarg.h>
 #include <stdbool.h>
@@ -107,14 +106,51 @@ static bool	 is_xo_style_encoding;
 static bool	 show_path_state = false;
 
 /*
- * Default protocols to use if no -P was defined.
+ * Protocols that we support.
+ * TODO: merge unix(4) protocols into here.
  */
-static const char *default_protos[] = {"sctp", "tcp", "udp", "udplite",
-    "divert" };
-static size_t	   default_numprotos = nitems(default_protos);
-
-static int	*protos;	/* protocols to use */
-static size_t	 numprotos;	/* allocated size of protos[] */
+struct proto;
+typedef void gather_func_t(struct proto *);
+static gather_func_t gather_sctp, gather_inet;
+static struct proto {
+	gather_func_t	*gather;
+	const char	*name;
+	const char	*pcblist;
+	union {
+			int protonum;	/* gather_inet() */
+	};
+	bool disabled;
+} protos[] = {
+	{
+		.name = "sctp",
+		.gather = gather_sctp,
+		.pcblist = "net.inet.sctp.assoclist",
+		.protonum = IPPROTO_SCTP,
+	},
+	{
+		.name = "tcp",
+		.gather = gather_inet,
+		.pcblist = "net.inet.tcp.pcblist",
+		.protonum = IPPROTO_TCP,
+	},
+	{
+		.name = "udp",
+		.gather = gather_inet,
+		.pcblist = "net.inet.udp.pcblist",
+		.protonum = IPPROTO_UDP,
+	},
+	{
+		.name = "udplite",
+		.gather = gather_inet,
+		.pcblist = "net.inet.udplite.pcblist",
+		.protonum = IPPROTO_UDPLITE,
+	},
+	{
+		.name = "divert",
+		.gather = gather_inet,
+		.pcblist = "net.inet.divert.pcblist",
+	},
+};
 
 /*
  * Show sockets for user username or UID specified
@@ -236,63 +272,26 @@ need_nosocks(void)
 	return !(opt_F || (opt_j >= 0));
 }
 
-static int
-get_proto_type(const char *proto)
-{
-	struct protoent *pent;
-
-	if (strlen(proto) == 0)
-		return (0);
-	if (capnetdb != NULL)
-		pent = cap_getprotobyname(capnetdb, proto);
-	else
-		pent = getprotobyname(proto);
-	if (pent == NULL) {
-		xo_warn("cap_getprotobyname");
-		return (-1);
-	}
-	return (pent->p_proto);
-}
-
 static void
-init_protos(int num)
-{
-	int proto_count = 0;
-
-	if (num > 0) {
-		proto_count = num;
-	} else {
-		/* Find the maximum number of possible protocols. */
-		while (getprotoent() != NULL)
-			proto_count++;
-		endprotoent();
-	}
-
-	if ((protos = malloc(sizeof(int) * proto_count)) == NULL)
-		xo_err(1, "malloc");
-	numprotos = proto_count;
-}
-
-static int
 parse_protos(char *protospec)
 {
 	char *prot;
-	int proto_type, proto_index;
+	u_int i;
 
-	if (protospec == NULL)
-		return (-1);
+	for (i = 0; i < nitems(protos); i++)
+		protos[i].disabled = true;
 
-	init_protos(0);
-	proto_index = 0;
 	while ((prot = strsep(&protospec, ",")) != NULL) {
 		if (strlen(prot) == 0)
 			continue;
-		proto_type = get_proto_type(prot);
-		if (proto_type != -1)
-			protos[proto_index++] = proto_type;
+		for (i = 0; i < nitems(protos); i++)
+			if (strcmp(prot, protos[i].name) == 0) {
+				protos[i].disabled = false;
+				break;
+			}
+		if (i == nitems(protos))
+			xo_errx(1, "protocol %s not supported", prot);
 	}
-	numprotos = proto_index;
-	return (proto_index);
 }
 
 static void
@@ -349,7 +348,7 @@ free_socket(struct sock *sock)
 }
 
 static void
-gather_sctp(void)
+gather_sctp(struct proto *proto)
 {
 	struct sock *sock;
 	struct addr *laddr, *prev_laddr, *faddr, *prev_faddr;
@@ -357,7 +356,6 @@ gather_sctp(void)
 	struct xsctp_tcb *xstcb;
 	struct xsctp_raddr *xraddr;
 	struct xsctp_laddr *xladdr;
-	const char *varname;
 	size_t len, offset;
 	char *buf;
 	int vflag;
@@ -369,8 +367,7 @@ gather_sctp(void)
 	if (opt_6)
 		vflag |= INP_IPV6;
 
-	varname = "net.inet.sctp.assoclist";
-	if (cap_sysctlbyname(capsysctl, varname, 0, &len, 0, 0) < 0) {
+	if (cap_sysctlbyname(capsysctl, proto->pcblist, 0, &len, 0, 0) < 0) {
 		if (errno != ENOENT)
 			xo_err(1, "cap_sysctlbyname()");
 		return;
@@ -379,7 +376,7 @@ gather_sctp(void)
 		xo_err(1, "malloc()");
 		return;
 	}
-	if (cap_sysctlbyname(capsysctl, varname, buf, &len, 0, 0) < 0) {
+	if (cap_sysctlbyname(capsysctl, proto->pcblist, buf, &len, 0, 0) < 0) {
 		xo_err(1, "cap_sysctlbyname()");
 		free(buf);
 		return;
@@ -618,7 +615,7 @@ gather_sctp(void)
 }
 
 static void
-gather_inet(int proto)
+gather_inet(struct proto *proto)
 {
 	struct xinpgen *xig, *exig;
 	struct xinpcb *xip;
@@ -626,7 +623,7 @@ gather_inet(int proto)
 	struct xsocket *so;
 	struct sock *sock;
 	struct addr *laddr, *faddr;
-	const char *varname, *protoname;
+	const char *protoname = proto->name;
 	size_t len, bufsize;
 	void *buf;
 	int retry, vflag;
@@ -637,27 +634,6 @@ gather_inet(int proto)
 	if (opt_6)
 		vflag |= INP_IPV6;
 
-	switch (proto) {
-	case IPPROTO_TCP:
-		varname = "net.inet.tcp.pcblist";
-		protoname = "tcp";
-		break;
-	case IPPROTO_UDP:
-		varname = "net.inet.udp.pcblist";
-		protoname = "udp";
-		break;
-	case IPPROTO_UDPLITE:
-		varname = "net.inet.udplite.pcblist";
-		protoname = "udplite";
-		break;
-	case IPPROTO_DIVERT:
-		varname = "net.inet.divert.pcblist";
-		protoname = "div";
-		break;
-	default:
-		xo_errx(1, "protocol %d not supported", proto);
-	}
-
 	buf = NULL;
 	bufsize = 8192;
 	retry = 5;
@@ -666,8 +642,8 @@ gather_inet(int proto)
 			if ((buf = realloc(buf, bufsize)) == NULL)
 				xo_err(1, "realloc()");
 			len = bufsize;
-			if (cap_sysctlbyname(capsysctl, varname, buf, &len,
-			    NULL, 0) == 0)
+			if (cap_sysctlbyname(capsysctl, proto->pcblist, buf,
+			    &len, NULL, 0) == 0)
 				break;
 			if (errno == ENOENT)
 				goto out;
@@ -689,23 +665,17 @@ gather_inet(int proto)
 		xig = (struct xinpgen *)(void *)((char *)xig + xig->xig_len);
 		if (xig >= exig)
 			break;
-		switch (proto) {
-		case IPPROTO_TCP:
+		if (proto->protonum == IPPROTO_TCP) {
 			xtp = (struct xtcpcb *)xig;
 			xip = &xtp->xt_inp;
 			if (!check_ksize(xtp->xt_len, struct xtcpcb))
 				goto out;
-			protoname = xtp->t_flags & TF_TOE ? "toe" : "tcp";
-			break;
-		case IPPROTO_UDP:
-		case IPPROTO_UDPLITE:
-		case IPPROTO_DIVERT:
+			if (xtp->t_flags & TF_TOE)
+				protoname = "toe";
+		} else {
 			xip = (struct xinpcb *)xig;
 			if (!check_ksize(xip->xi_len, struct xinpcb))
 				goto out;
-			break;
-		default:
-			xo_errx(1, "protocol %d not supported", proto);
 		}
 		so = &xip->xi_socket;
 		if ((xip->inp_vflag & vflag) == 0)
@@ -743,7 +713,7 @@ gather_inet(int proto)
 		sock->socket = so->xso_so;
 		sock->pcb = so->so_pcb;
 		sock->splice_socket = so->so_splice_so;
-		sock->proto = proto;
+		sock->proto = proto->protonum;
 		sock->inp_gencnt = xip->inp_gencnt;
 		sock->fibnum = so->so_fibnum;
 		if (xip->inp_vflag & INP_IPV4) {
@@ -759,14 +729,14 @@ gather_inet(int proto)
 			sockaddr(&faddr->address, sock->family,
 			    &xip->in6p_faddr, xip->inp_fport);
 		}
-		if (proto == IPPROTO_TCP)
+		if (proto->protonum == IPPROTO_TCP)
 			faddr->encaps_port = xtp->xt_encaps_port;
 		laddr->next = NULL;
 		faddr->next = NULL;
 		sock->laddr = laddr;
 		sock->faddr = faddr;
 		sock->vflag = xip->inp_vflag;
-		if (proto == IPPROTO_TCP) {
+		if (proto->protonum == IPPROTO_TCP) {
 			sock->state = xtp->t_state;
 			sock->bblog_state = xtp->t_logstate;
 			memcpy(sock->stack, xtp->xt_stack,
@@ -1776,26 +1746,6 @@ out:
 	cap_endpwent(cappwd);
 }
 
-static int
-set_default_protos(void)
-{
-	struct protoent *prot;
-	const char *pname;
-	size_t pindex;
-
-	init_protos(default_numprotos);
-
-	for (pindex = 0; pindex < default_numprotos; pindex++) {
-		pname = default_protos[pindex];
-		prot = cap_getprotobyname(capnetdb, pname);
-		if (prot == NULL)
-			xo_err(1, "cap_getprotobyname: %s", pname);
-		protos[pindex] = prot->p_proto;
-	}
-	numprotos = pindex;
-	return (pindex);
-}
-
 /*
  * Return the vnet property of the jail, or -1 on error.
  */
@@ -1881,8 +1831,8 @@ main(int argc, char *argv[])
 	cap_net_limit_t *limit;
 	const char *pwdcmds[] = { "setpassent", "getpwuid", "getpwnam" };
 	const char *pwdfields[] = { "pw_name", "pw_uid" };
-	int protos_defined = -1;
-	int o, i, err;
+	bool protos_defined = false;
+	int o, err;
 
 	argc = xo_parse_args(argc, argv);
 	if (argc < 0)
@@ -1953,7 +1903,8 @@ main(int argc, char *argv[])
 			}
 			break;
 		case 'P':
-			protos_defined = parse_protos(optarg);
+			parse_protos(optarg);
+			protos_defined = true;
 			break;
 		case 'q':
 			opt_q = true;
@@ -2032,24 +1983,19 @@ main(int argc, char *argv[])
 	if (opt_F && !parse_filter_user())
 		xo_errx(1, "Invalid username or UID specified");
 
-	if ((!opt_4 && !opt_6) && protos_defined != -1)
+	if ((!opt_4 && !opt_6) && protos_defined)
 		opt_4 = opt_6 = true;
 	if (!opt_4 && !opt_6 && !opt_u)
 		opt_4 = opt_6 = opt_u = true;
-	if ((opt_4 || opt_6) && protos_defined == -1)
-		protos_defined = set_default_protos();
 	if (!opt_c && !opt_l)
 		opt_c = opt_l = true;
 
-	if (opt_4 || opt_6) {
-		for (i = 0; i < protos_defined; i++)
-			if (protos[i] == IPPROTO_SCTP)
-				gather_sctp();
-			else
-				gather_inet(protos[i]);
-	}
+	if (opt_4 || opt_6)
+		for (u_int i = 0; i < nitems(protos); i++)
+			if (!protos[i].disabled)
+				protos[i].gather(&protos[i]);
 
-	if (opt_u || (protos_defined == -1 && !opt_4 && !opt_6)) {
+	if (opt_u || (!protos_defined && !opt_4 && !opt_6)) {
 		gather_unix(SOCK_STREAM);
 		gather_unix(SOCK_DGRAM);
 		gather_unix(SOCK_SEQPACKET);

usr.bin/sockstat/sockstat.1

@@ -25,7 +25,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd April 15, 2026
+.Dd June 8, 2026
 .Dt SOCKSTAT 1
 .Os
 .Sh NAME
@@ -114,9 +114,14 @@ Only show sockets of the specified
 .Ar protocols .
 The
 .Ar protocols
-argument is a comma-separated list of protocol names,
-as they are defined in
-.Xr protocols 5 .
+argument is a comma-separated list of protocol names.
+Recognized protocols are
+.Qq tcp ,
+.Qq sctp ,
+.Qq udp ,
+.Qq udplite
+and
+.Qq divert .
 .It Fl q
 Quiet mode, do not print the header line.
 .It Fl S
@@ -264,7 +269,11 @@ $ sockstat --libxo json,pretty
 .Xr libxo 3 ,
 .Xr inet 4 ,
 .Xr inet6 4 ,
-.Xr protocols 5 ,
+.Xr divert 4 ,
+.Xr tcp 4 ,
+.Xr sctp 4 ,
+.Xr udp 4 ,
+.Xr unix 4 ,
 .Xr xo_options 7
 .Sh HISTORY
 The