cfg.rl: Build with compact table-driven Ragel mode.

This reduces binary size by over 10% and the small hit to
config file parsing performance is insignificant and only
paid once at startup.

Makefile

@@ -23,7 +23,7 @@ ifchd-parse.c:
 	ragel -G2 -o ifchd-parse.c ifchd-parse.rl
 
 cfg.c:
-	ragel -G2 -o cfg.c cfg.rl
+	ragel -T0 -o cfg.c cfg.rl
 
 ragel: ifchd-parse.c cfg.c
 

cfg.rl

@@ -9,6 +9,7 @@
 #include <limits.h>
 #include "ndhc-defines.h"
 #include "cfg.h"
+#include "sys.h"
 #include "arp.h"
 #include "ndhc.h"
 #include "ifchd.h"
@@ -17,6 +18,43 @@
 #include "nk/privs.h"
 #include "nk/io.h"
 
+static bool xisxdigit(int c)
+{
+    return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f');
+}
+
+static bool is_string_hwaddr(const char *str, size_t slen)
+{
+    return slen == 17 && str[2] == ':' && str[5] == ':' && str[8] == ':' &&
+        str[11] == ':' && str[14] == ':' &&
+        xisxdigit(str[0]) && xisxdigit(str[1]) && xisxdigit(str[3]) &&
+        xisxdigit(str[4]) && xisxdigit(str[6]) && xisxdigit(str[7]) &&
+        xisxdigit(str[9]) && xisxdigit(str[10]) && xisxdigit(str[12]) &&
+        xisxdigit(str[13]) && xisxdigit(str[15]) && xisxdigit(str[16]);
+}
+
+static int get_clientid_string(const char *str, size_t slen)
+{
+    if (!slen)
+        return -1;
+    if (!is_string_hwaddr(str, slen)) {
+        client_config.clientid[0] = 0;
+        memcpy(client_config.clientid + 1, str,
+               min_size_t(slen, sizeof client_config.clientid - 1));
+        client_config.clientid_len = slen + 1;
+        return 0;
+    }
+
+    uint8_t mac[6];
+    for (size_t i = 0; i < sizeof mac; ++i)
+        mac[i] = strtol(str+i*3, (char **)0, 16);
+    client_config.clientid[0] = 1; // Ethernet MAC type
+    memcpy(client_config.clientid + 1, mac,
+           min_size_t(sizeof mac, sizeof client_config.clientid - 1));
+    client_config.clientid_len = 7;
+    return 1;
+}
+
 static void copy_cmdarg(char *dest, const char *src,
                         size_t destlen, const char *argname)
 {

examples/s6.run

@@ -1,6 +1,8 @@
 #!/bin/execlineb -P
 fdmove -c 2 1
-backtick OLDEXTIP { cat /etc/firewall/tmp/OLDEXTIP }
+backtick OLDEXTIP { cat /etc/ndhc/LEASE-wan0 }
 importas OLDEXTIP OLDEXTIP
-/sbin/ndhc -c /etc/ndhc/wan0.conf -r $OLDEXTIP
+ifelse { eltest -n $OLDEXTIP }
+{ /sbin/ndhc -c /etc/ndhc/wan0.conf -r $OLDEXTIP }
+/sbin/ndhc -c /etc/ndhc/wan0.conf
 

ifset.c

@@ -29,15 +29,14 @@
 
 static uint32_t ifset_nl_seq = 1;
 
-// 32-bit position values are relatively prime to 37, so the residue mod37
-// gives a unique mapping for each value.  Gives correct result for v=0.
-static int trailz(uint32_t v)
+// Portable ctz() that gives a defined result for x == 0.
+static int trailz(uint32_t x)
 {
-    static const int bpm37[] = {
-        32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13, 4, 7, 17,
-        0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9, 5, 20, 8, 19, 18
+    static const int ctzt[32] = {
+        0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
+        31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10,
     };
-    return bpm37[(-v & v) % 37];
+    return x ? ctzt[((x & -x) * 0x077cb531u) >> 27] : 32;
 }
 
 // sn must be in network order

leasefile.c

@@ -33,7 +33,7 @@ void open_leasefile(void)
 {
     char leasefile[PATH_MAX];
     get_leasefile_path(leasefile, sizeof leasefile, client_config.interface);
-    leasefilefd = open(leasefile, O_WRONLY|O_TRUNC|O_CREAT|O_CLOEXEC, 0644);
+    leasefilefd = open(leasefile, O_WRONLY|O_CREAT|O_CLOEXEC, 0644);
     if (leasefilefd < 0)
         suicide("%s: (%s) Failed to create lease file '%s': %s",
                 client_config.interface, __func__, leasefile, strerror(errno));
@@ -59,6 +59,10 @@ static void do_write_leasefile(struct in_addr ipnum)
         log_line("%s: (%s) memccpy failed", client_config.interface, __func__);
         return;
     }
+    size_t outlen = strlen(out);
+    // Make sure that we're not overwriting the leasefile with an invalid
+    // IP address.  This is a very minimal check.
+    if (outlen < 7) return;
     if (safe_ftruncate(leasefilefd, 0)) {
         log_line("%s: (%s) Failed to truncate lease file: %s",
                  client_config.interface, __func__, strerror(errno));
@@ -69,7 +73,6 @@ static void do_write_leasefile(struct in_addr ipnum)
                  client_config.interface, __func__, strerror(errno));
         return;
     }
-    size_t outlen = strlen(out);
     ssize_t ret = safe_write(leasefilefd, out, outlen);
     if (ret < 0 || (size_t)ret != outlen)
         log_line("%s: (%s) Failed to write ip to lease file.",

ndhc.c

@@ -10,7 +10,6 @@
 #include <signal.h>
 #include <time.h>
 #include <string.h>
-#include <ctype.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
@@ -198,41 +197,6 @@ static void setup_signals_ndhc(void)
             suicide("sigaction failed");
 }
 
-static int is_string_hwaddr(const char *str, size_t slen)
-{
-    if (slen == 17 && str[2] == ':' && str[5] == ':' && str[8] == ':' &&
-        str[11] == ':' && str[14] == ':' &&
-        isxdigit(str[0]) && isxdigit(str[1]) && isxdigit(str[3]) &&
-        isxdigit(str[4]) && isxdigit(str[6]) && isxdigit(str[7]) &&
-        isxdigit(str[9]) && isxdigit(str[10]) && isxdigit(str[12]) &&
-        isxdigit(str[13]) && isxdigit(str[15]) && isxdigit(str[16])
-        )
-        return 1;
-    return 0;
-}
-
-int get_clientid_string(const char *str, size_t slen)
-{
-    if (!slen)
-        return -1;
-    if (!is_string_hwaddr(str, slen)) {
-        client_config.clientid[0] = 0;
-        memcpy(client_config.clientid + 1, str,
-               min_size_t(slen, sizeof client_config.clientid - 1));
-        client_config.clientid_len = slen + 1;
-        return 0;
-    }
-
-    uint8_t mac[6];
-    for (size_t i = 0; i < sizeof mac; ++i)
-        mac[i] = strtol(str+i*3, (char **)0, 16);
-    client_config.clientid[0] = 1; // Ethernet MAC type
-    memcpy(client_config.clientid + 1, mac,
-           min_size_t(sizeof mac, sizeof client_config.clientid - 1));
-    client_config.clientid_len = 7;
-    return 1;
-}
-
 static void fail_if_state_dir_dne(void)
 {
     if (strlen(state_dir) == 0)
@@ -257,24 +221,21 @@ static void do_ndhc_work(void)
     setup_signals_ndhc();
     start_dhcp_listen(&cs);
 
-    struct pollfd pfds[6] = {0};
-    pfds[0].fd = cs.nlFd;
-    pfds[0].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP;
-    pfds[1].fd = ifchStream[0];
-    pfds[1].events = POLLHUP|POLLERR|POLLRDHUP;
-    pfds[2].fd = sockdStream[0];
-    pfds[2].events = POLLHUP|POLLERR|POLLRDHUP;
-    pfds[3].fd = cs.rfkillFd;
-    pfds[3].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP;
-    // These can change on the fly.
-    pfds[4].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP;
-    pfds[5].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP;
-
+    struct pollfd pfds[] = {
+        [0] = { .fd = cs.nlFd,          .events = POLLIN|POLLHUP|POLLERR|POLLRDHUP },
+        [1] = { .fd = ifchStream[0],    .events = POLLHUP|POLLERR|POLLRDHUP },
+        [2] = { .fd = sockdStream[0],   .events = POLLHUP|POLLERR|POLLRDHUP },
+        [6] = { .fd = scriptdStream[0], .events = POLLHUP|POLLERR|POLLRDHUP },
+        [3] = { .fd = cs.rfkillFd,      .events = POLLIN|POLLHUP|POLLERR|POLLRDHUP },
+        // These can change on the fly.
+        [4] = { .events = POLLIN|POLLHUP|POLLERR|POLLRDHUP },
+        [5] = { .events = POLLIN|POLLHUP|POLLERR|POLLRDHUP },
+    };
     for (;;) {
         pfds[4].fd = cs.arpFd;
         pfds[5].fd = cs.listenFd;
         had_event = false;
-        if (poll(pfds, 6, timeout) < 0) {
+        if (poll(pfds, 7, timeout) < 0) {
             if (errno != EINTR) suicide("poll failed");
         }
 
@@ -300,6 +261,9 @@ static void do_ndhc_work(void)
         if (pfds[2].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
             exit(EXIT_FAILURE);
         }
+        if (pfds[6].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
+            exit(EXIT_FAILURE);
+        }
         if (pfds[3].revents & POLLIN) {
             had_event = true;
             sev_rfk = rfkill_get(&cs, 1, client_config.rfkillIdx);
@@ -411,7 +375,7 @@ int ifchStream[2];
 int sockdSock[2];
 int sockdStream[2];
 int scriptdSock[2];
-int scriptdStream[2];
+int scriptdStream[2] = { -1, -1 };
 
 static void create_ifch_ipc_sockets(void) {
     if (socketpair(AF_UNIX, SOCK_DGRAM, 0, ifchSock) < 0)

ndhc.h

@@ -83,7 +83,6 @@ bool carrier_isup(void);
 void set_client_addr(const char *v);
 void show_usage(void);
 void signal_exit(int status);
-int get_clientid_string(const char *str, size_t slen);
 void print_version(void);
 
 static inline void advance_xid(struct client_state_t *cs) {

nk/random.c

@@ -1,17 +1,16 @@
-// Copyright 2013-2018 Nicholas J. Kain <njkain at gmail dot com>
+// Copyright 2013-2022 Nicholas J. Kain <njkain at gmail dot com>
 // SPDX-License-Identifier: MIT
 #include <stdint.h>
 #include "nk/hwrng.h"
 #include "nk/random.h"
 
-// GJrand64: https://gjrand.sourceforge.net
+// SFC64 modified to use a Weyl counter.
 
 void nk_random_init(struct nk_random_state *s)
 {
-    nk_hwrng_bytes(s->seed, sizeof(uint64_t) * 2);
-    s->seed[2] = 2000001;
-    s->seed[3] = 0;
-    for (size_t i = 0; i < 14; ++i) nk_random_u64(s);
+    nk_hwrng_bytes(s->seed, sizeof(uint64_t) * 3);
+    s->seed[3] = 1;
+    for (size_t i = 0; i < 12; ++i) nk_random_u64(s);
 }
 
 static inline uint64_t rotl64(const uint64_t x, int k) {
@@ -20,17 +19,11 @@ static inline uint64_t rotl64(const uint64_t x, int k) {
 
 uint64_t nk_random_u64(struct nk_random_state *s)
 {
-    s->seed[1] += s->seed[2];
-    s->seed[0] = rotl64(s->seed[0], 32);
-    s->seed[2] ^= s->seed[1];
-    s->seed[3] += 0x55aa96a5;
-    s->seed[0] += s->seed[1];
-    s->seed[2] = rotl64(s->seed[2], 23);
-    s->seed[1] ^= s->seed[0];
-    s->seed[0] += s->seed[2];
-    s->seed[1] = rotl64(s->seed[1], 19);
-    s->seed[2] += s->seed[0];
-    s->seed[1] += s->seed[3];
-    return s->seed[0];
+    const uint64_t t = (s->seed[0] + s->seed[1]) ^ s->seed[3];
+    s->seed[3] += 0x6a09e667a7541669ull;
+    s->seed[0] = s->seed[1] ^ (s->seed[1] >> 11);
+    s->seed[1] = s->seed[2] + (s->seed[2] << 3);
+    s->seed[2] = rotl64(s->seed[2], 24) + t;
+    return t;
 }
 

scriptd.c

@@ -10,6 +10,7 @@
 #include <sys/wait.h>
 #include <sys/prctl.h>
 #include <sys/stat.h>
+#include <fcntl.h>
 #include "nk/log.h"
 #include "nk/io.h"
 #include "nk/pspawn.h"
@@ -138,7 +139,7 @@ static void setup_signals_scriptd(void)
 
     struct sigaction sa = {
         .sa_handler = signal_handler,
-        .sa_flags = SA_RESTART|SA_NOCLDWAIT,
+        .sa_flags = SA_RESTART,
     };
     if (sigemptyset(&sa.sa_mask))
         suicide("sigemptyset failed");
@@ -153,6 +154,8 @@ void scriptd_main(void)
     prctl(PR_SET_NAME, "ndhc: scriptd");
     umask(077);
     setup_signals_scriptd();
+    fcntl(scriptdSock[1], F_SETFD, FD_CLOEXEC);
+    fcntl(scriptdStream[1], F_SETFD, FD_CLOEXEC);
     do_scriptd_work();
 }