ntp: simplifications; libbb: simpler resolution of numeric hostnames

function                                             old     new   delta
str2sockaddr                                         405     567    +162
ntp_init                                             310     317      +7
scale_interval                                        58      59      +1
error_interval                                        22      23      +1
ntpd_main                                           3257    3214     -43
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 171/-43)           Total: 128 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 108 insertions, 100 deletions

diff --git a/networking/ntpd.c b/networking/ntpd.c
index 8ee42e627..4e661ce98 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -5,7 +5,6 @@
  *
  * Licensed under GPLv2, see file LICENSE in this tarball for details.
  */
-
 #include "libbb.h"
 #include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
 
@@ -59,30 +58,32 @@ typedef struct {
         uint16_t fractions;
 } s_fixedpt_t;
 
-#define NTP_DIGESTSIZE          16
-#define NTP_MSGSIZE_NOAUTH      48
-#define NTP_MSGSIZE             (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE)
+enum {
+        NTP_DIGESTSIZE     = 16,
+        NTP_MSGSIZE_NOAUTH = 48,
+        NTP_MSGSIZE        = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
+};
 
 typedef struct {
-        uint8_t status; /* status of local clock and leap info */
-        uint8_t stratum;        /* Stratum level */
-        uint8_t ppoll;          /* poll value */
-        int8_t precision;
+        uint8_t     status;     /* status of local clock and leap info */
+        uint8_t     stratum;    /* stratum level */
+        uint8_t     ppoll;      /* poll value */
+        int8_t      precision;
         s_fixedpt_t rootdelay;
         s_fixedpt_t dispersion;
-        uint32_t refid;
+        uint32_t    refid;
         l_fixedpt_t reftime;
         l_fixedpt_t orgtime;
         l_fixedpt_t rectime;
         l_fixedpt_t xmttime;
-        uint32_t keyid;
-        uint8_t digest[NTP_DIGESTSIZE];
+        uint32_t    keyid;
+        uint8_t     digest[NTP_DIGESTSIZE];
 } ntp_msg_t;
 
 typedef struct {
-        int                     fd;
-        ntp_msg_t               msg;
-        double                  xmttime;
+        int       fd;
+        ntp_msg_t msg;
+        double    xmttime;
 } ntp_query_t;
 
 enum {
@@ -97,6 +98,7 @@ enum {
         /* Status Masks */
         MODE_MASK       = (7 << 0),
         VERSION_MASK    = (7 << 3),
+        VERSION_SHIFT   = 3,
         LI_MASK         = (3 << 6),
 
         /* Mode values */
@@ -107,7 +109,7 @@ enum {
         MODE_SERVER     = 4,    /* server */
         MODE_BROADCAST  = 5,    /* broadcast */
         MODE_RES1       = 6,    /* reserved for NTP control message */
-        MODE_RES2       = 7     /* reserved for private use */
+        MODE_RES2       = 7,    /* reserved for private use */
 };
 
 #define JAN_1970        2208988800UL    /* 1970 - 1900 in seconds */
@@ -115,7 +117,7 @@ enum {
 enum client_state {
         STATE_NONE,
         STATE_QUERY_SENT,
-        STATE_REPLY_RECEIVED
+        STATE_REPLY_RECEIVED,
 };
 
 typedef struct {
@@ -132,24 +134,27 @@ typedef struct {
 } ntp_status_t;
 
 typedef struct {
-        ntp_status_t            status;
-        double                  offset;
-        double                  delay;
-        double                  error;
-        time_t                  rcvd;
-        uint8_t                 good;
+        ntp_status_t    status;
+        double          offset;
+        double          delay;
+        double          error;
+        time_t          rcvd;
+        uint8_t         good;
 } ntp_offset_t;
 
 typedef struct {
+//TODO:
+// (1) store dotted addr str, to avoid constant translations
+// (2) periodically re-resolve DNS names
         len_and_sockaddr        *lsa;
-        ntp_query_t              query;
-        ntp_offset_t             reply[OFFSET_ARRAY_SIZE];
-        ntp_offset_t             update;
-        enum client_state        state;
-        time_t                   next;
-        time_t                   deadline;
-        uint8_t                  shift;
-        uint8_t                  trustlevel;
+        ntp_query_t             query;
+        ntp_offset_t            reply[OFFSET_ARRAY_SIZE];
+        ntp_offset_t            update;
+        enum client_state       state;
+        time_t                  next;
+        time_t                  deadline;
+        uint8_t                 shift;
+        uint8_t                 trustlevel;
 } ntp_peer_t;
 
 enum {
@@ -211,8 +216,7 @@ add_peers(const char *s)
 static double
 gettime(void)
 {
-        struct timeval  tv;
-
+        struct timeval tv;
         gettimeofday(&tv, NULL); /* never fails */
         return (tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec);
 }
@@ -228,45 +232,43 @@ d_to_tv(double d, struct timeval *tv)
 static double
 lfp_to_d(l_fixedpt_t lfp)
 {
-        double  ret;
-
+        double ret;
         lfp.int_partl = ntohl(lfp.int_partl);
         lfp.fractionl = ntohl(lfp.fractionl);
-        ret = (double)(lfp.int_partl) + ((double)lfp.fractionl / UINT_MAX);
+        ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
         return ret;
 }
 
-#if ENABLE_FEATURE_NTPD_SERVER
-static l_fixedpt_t
-d_to_lfp(double d)
-{
-        l_fixedpt_t     lfp;
-
-        lfp.int_partl = htonl((uint32_t)d);
-        lfp.fractionl = htonl((uint32_t)((d - (u_int32_t)d) * UINT_MAX));
-        return lfp;
-}
-#endif
-
 static double
 sfp_to_d(s_fixedpt_t sfp)
 {
-        double  ret;
-
+        double ret;
         sfp.int_parts = ntohs(sfp.int_parts);
         sfp.fractions = ntohs(sfp.fractions);
-        ret = (double)(sfp.int_parts) + ((double)sfp.fractions / USHRT_MAX);
+        ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
         return ret;
 }
 
 #if ENABLE_FEATURE_NTPD_SERVER
+static l_fixedpt_t
+d_to_lfp(double d)
+{
+        l_fixedpt_t lfp;
+        lfp.int_partl = (uint32_t)d;
+        lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
+        lfp.int_partl = htonl(lfp.int_partl);
+        lfp.fractionl = htonl(lfp.fractionl);
+        return lfp;
+}
+
 static s_fixedpt_t
 d_to_sfp(double d)
 {
-        s_fixedpt_t     sfp;
-
-        sfp.int_parts = htons((uint16_t)d);
-        sfp.fractions = htons((uint16_t)((d - (u_int16_t)d) * USHRT_MAX));
+        s_fixedpt_t sfp;
+        sfp.int_parts = (uint16_t)d;
+        sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
+        sfp.int_parts = htons(sfp.int_parts);
+        sfp.fractions = htons(sfp.fractions);
         return sfp;
 }
 #endif
@@ -282,9 +284,8 @@ static time_t
 error_interval(void)
 {
         time_t interval, r;
-
         interval = INTERVAL_QUERY_PATHETIC * QSCALE_OFF_MAX / QSCALE_OFF_MIN;
-        r = random() % (interval / 10);
+        r = (unsigned)random() % (unsigned long)(interval / 10);
         return (interval + r);
 }
 
@@ -352,12 +353,8 @@ client_query(ntp_peer_t *p)
 static int
 offset_compare(const void *aa, const void *bb)
 {
-        const ntp_peer_t * const *a;
-        const ntp_peer_t * const *b;
-
-        a = aa;
-        b = bb;
-
+        const ntp_peer_t *const *a = aa;
+        const ntp_peer_t *const *b = bb;
         if ((*a)->update.offset < (*b)->update.offset)
                 return -1;
         return ((*a)->update.offset > (*b)->update.offset);
@@ -368,7 +365,6 @@ updated_scale(double offset)
 {
         if (offset < 0)
                 offset = -offset;
-
         if (offset > QSCALE_OFF_MAX)
                 return 1;
         if (offset < QSCALE_OFF_MIN)
@@ -559,9 +555,8 @@ static time_t
 scale_interval(time_t requested)
 {
         time_t interval, r;
-
         interval = requested * G.scale;
-        r = random() % MAX(5, interval / 10);
+        r = (unsigned)random() % (unsigned long)(MAX(5, interval / 10));
         return (interval + r);
 }
 
@@ -577,9 +572,10 @@ client_dispatch(ntp_peer_t *p)
 
         addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
 
-        size = recvfrom(p->query.fd, &msg, sizeof(msg), 0, NULL, NULL);
+//TODO: use MSG_DONTWAIT flag?
+        size = recv(p->query.fd, &msg, sizeof(msg), 0);
         if (size == -1) {
-                bb_perror_msg("recvfrom(%s) error", addr);
+                bb_perror_msg("recv(%s) error", addr);
                 if (errno == EHOSTUNREACH || errno == EHOSTDOWN
                  || errno == ENETUNREACH || errno == ENETDOWN
                  || errno == ECONNREFUSED || errno == EADDRNOTAVAIL
@@ -693,48 +689,58 @@ client_dispatch(ntp_peer_t *p)
 static void
 server_dispatch(int fd)
 {
-        ssize_t                 size;
-        uint8_t                 version;
-        double                  rectime;
-        len_and_sockaddr        *to;
-        struct sockaddr         *from;
-        ntp_msg_t               query, reply;
+        ssize_t          size;
+        uint8_t          version;
+        double           rectime;
+        len_and_sockaddr *to;
+        struct sockaddr  *from;
+        ntp_msg_t        msg;
+        uint8_t          query_status;
+        uint8_t          query_ppoll;
+        l_fixedpt_t      query_xmttime;
 
         to = get_sock_lsa(G.listen_fd);
         from = xzalloc(to->len);
 
-        size = recv_from_to(fd, &query, sizeof(query), 0, from, &to->u.sa, to->len);
-        if (size == -1)
-                bb_error_msg_and_die("recv_from_to");
+//TODO: use MGS_DONTWAIT flag?
+        size = recv_from_to(fd, &msg, sizeof(msg), 0, from, &to->u.sa, to->len);
         if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
-                char *addr = xmalloc_sockaddr2dotted_noport(from);
+                char *addr;
+                if (size < 0)
+                        bb_error_msg_and_die("recv_from_to");
+                addr = xmalloc_sockaddr2dotted_noport(from);
                 bb_error_msg("malformed packet received from %s", addr);
                 free(addr);
                 goto bail;
         }
 
-        rectime = gettime();
-        version = (query.status & VERSION_MASK) >> 3;
+        query_status = msg.status;
+        query_ppoll = msg.ppoll;
+        query_xmttime = msg.xmttime;
 
-        memset(&reply, 0, sizeof(reply));
-        reply.status = G.status.synced ? G.status.leap : LI_ALARM;
-        reply.status |= (query.status & VERSION_MASK);
-        reply.status |= ((query.status & MODE_MASK) == MODE_CLIENT) ?
+        /* Build a reply packet */
+        memset(&msg, 0, sizeof(msg));
+        msg.status = G.status.synced ? G.status.leap : LI_ALARM;
+        msg.status |= (query_status & VERSION_MASK);
+        msg.status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
                          MODE_SERVER : MODE_SYM_PAS;
-        reply.stratum = G.status.stratum;
-        reply.ppoll = query.ppoll;
-        reply.precision = G.status.precision;
-        reply.rectime = d_to_lfp(rectime);
-        reply.reftime = d_to_lfp(G.status.reftime);
-        reply.xmttime = d_to_lfp(gettime());
-        reply.orgtime = query.xmttime;
-        reply.rootdelay = d_to_sfp(G.status.rootdelay);
-        reply.refid = (version > 3) ? G.status.refid4 : G.status.refid;
+        msg.stratum = G.status.stratum;
+        msg.ppoll = query_ppoll;
+        msg.precision = G.status.precision;
+        rectime = gettime();
+        msg.xmttime = msg.rectime = d_to_lfp(rectime);
+        msg.reftime = d_to_lfp(G.status.reftime);
+        //msg.xmttime = d_to_lfp(gettime()); // = msg.rectime
+        msg.orgtime = query_xmttime;
+        msg.rootdelay = d_to_sfp(G.status.rootdelay);
+        version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
+        msg.refid = (version > (3 << VERSION_SHIFT)) ? G.status.refid4 : G.status.refid;
 
         /* We reply from the address packet was sent to,
          * this makes to/from look swapped here: */
-        sendmsg_wrap(fd, /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
-                        &reply, size);
+        sendmsg_wrap(fd,
+                /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
+                &msg, size);
 
  bail:
         free(to);
@@ -835,7 +841,8 @@ static NOINLINE void ntp_init(char **argv)
         unsigned opts;
         llist_t *peers;
 
-        tzset();
+        srandom(getpid());
+        /* tzset(); - why? it's called automatically when needed, no? */
 
         if (getuid())
                 bb_error_msg_and_die("need root privileges");
@@ -911,7 +918,7 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
 
         while (!bb_got_signal) {
                 llist_t *item;
-                unsigned i, j, idx_peers;
+                unsigned i, j, first_peer_idx;
                 unsigned sent_cnt, trial_cnt;
                 int nfds, timeout;
                 time_t nextaction;
@@ -926,7 +933,7 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
                         i++;
                 }
 #endif
-                idx_peers = i;
+                first_peer_idx = i;
                 sent_cnt = trial_cnt = 0;
                 for (item = g.ntp_peers; item != NULL; item = item->link) {
                         ntp_peer_t *p = (ntp_peer_t *) item->data;
@@ -960,7 +967,7 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
                         if (p->state == STATE_QUERY_SENT) {
                                 pfd[i].fd = p->query.fd;
                                 pfd[i].events = POLLIN;
-                                idx2peer[i - idx_peers] = p;
+                                idx2peer[i - first_peer_idx] = p;
                                 i++;
                         }
                 }
@@ -978,7 +985,8 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
 
                 j = 0;
 #if ENABLE_FEATURE_NTPD_SERVER
-                for (; nfds > 0 && j < idx_peers; j++) {
+//TODO: simplify. There is only one server fd!
+                for (; nfds > 0 && j < first_peer_idx; j++) {
                         if (pfd[j].revents & (POLLIN|POLLERR)) {
                                 nfds--;
                                 server_dispatch(pfd[j].fd);
@@ -988,7 +996,7 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
                 for (; nfds > 0 && j < i; j++) {
                         if (pfd[j].revents & (POLLIN|POLLERR)) {
                                 nfds--;
-                                client_dispatch(idx2peer[j - idx_peers]);
+                                client_dispatch(idx2peer[j - first_peer_idx]);
                         }
                 }
         } /* while (!bb_got_signal) */