traceroute: cleanup and fixes for packet size calculations

Remove FEATURE_TRACEROUTE_SOURCE_ROUTE: it's off by default, and
source routing is not used in real world.

Tested that "traceroute -n ::1 100" and "traceroute -n 127.0.0.1 100"
both send 100 byte IP packets (this matches what traceroute on Fedora
Rawhide is doing).

function                                             old     new   delta
common_traceroute_main                              3731    3738      +7

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

11 files changed, 40 insertions, 105 deletions

diff --git a/configs/TEST_nommu_defconfig b/configs/TEST_nommu_defconfig
index 5f822e598..20c2e1550 100644
--- a/configs/TEST_nommu_defconfig
+++ b/configs/TEST_nommu_defconfig
@@ -760,7 +760,6 @@ CONFIG_TFTP_DEBUG=y
 CONFIG_TRACEROUTE=y
 CONFIG_TRACEROUTE6=y
 CONFIG_FEATURE_TRACEROUTE_VERBOSE=y
-CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE=y
 CONFIG_FEATURE_TRACEROUTE_USE_ICMP=y
 CONFIG_UDHCPD=y
 CONFIG_DHCPRELAY=y
diff --git a/configs/TEST_noprintf_defconfig b/configs/TEST_noprintf_defconfig
index c56781e32..845032ea1 100644
--- a/configs/TEST_noprintf_defconfig
+++ b/configs/TEST_noprintf_defconfig
@@ -762,7 +762,6 @@ CONFIG_IFUPDOWN_IFSTATE_PATH=""
 # CONFIG_TRACEROUTE is not set
 # CONFIG_TRACEROUTE6 is not set
 # CONFIG_FEATURE_TRACEROUTE_VERBOSE is not set
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 # CONFIG_TUNCTL is not set
 # CONFIG_FEATURE_TUNCTL_UG is not set
diff --git a/configs/TEST_rh9_defconfig b/configs/TEST_rh9_defconfig
index 28daa6273..d8c5af4f7 100644
--- a/configs/TEST_rh9_defconfig
+++ b/configs/TEST_rh9_defconfig
@@ -778,7 +778,6 @@ CONFIG_FEATURE_TFTP_PROGRESS_BAR=y
 CONFIG_TRACEROUTE=y
 CONFIG_TRACEROUTE6=y
 CONFIG_FEATURE_TRACEROUTE_VERBOSE=y
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 CONFIG_TUNCTL=y
 CONFIG_FEATURE_TUNCTL_UG=y
diff --git a/configs/android2_defconfig b/configs/android2_defconfig
index fbc0da091..857f9f5df 100644
--- a/configs/android2_defconfig
+++ b/configs/android2_defconfig
@@ -814,7 +814,6 @@ CONFIG_TCPSVD=y
 # CONFIG_TRACEROUTE is not set
 # CONFIG_TRACEROUTE6 is not set
 # CONFIG_FEATURE_TRACEROUTE_VERBOSE is not set
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 CONFIG_TUNCTL=y
 CONFIG_FEATURE_TUNCTL_UG=y
diff --git a/configs/android_502_defconfig b/configs/android_502_defconfig
index 7ef1585fb..cd06affab 100644
--- a/configs/android_502_defconfig
+++ b/configs/android_502_defconfig
@@ -959,7 +959,6 @@ CONFIG_FEATURE_TFTP_PROGRESS_BAR=y
 CONFIG_TRACEROUTE=y
 CONFIG_TRACEROUTE6=y
 CONFIG_FEATURE_TRACEROUTE_VERBOSE=y
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 CONFIG_TUNCTL=y
 CONFIG_FEATURE_TUNCTL_UG=y
diff --git a/configs/android_defconfig b/configs/android_defconfig
index 4e0224207..f1ddc45d4 100644
--- a/configs/android_defconfig
+++ b/configs/android_defconfig
@@ -843,7 +843,6 @@ CONFIG_FEATURE_TFTP_PROGRESS_BAR=y
 CONFIG_TRACEROUTE=y
 # CONFIG_TRACEROUTE6 is not set
 CONFIG_FEATURE_TRACEROUTE_VERBOSE=y
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 CONFIG_TUNCTL=y
 CONFIG_FEATURE_TUNCTL_UG=y
diff --git a/configs/android_ndk_defconfig b/configs/android_ndk_defconfig
index d657d33e9..18651fd7c 100644
--- a/configs/android_ndk_defconfig
+++ b/configs/android_ndk_defconfig
@@ -869,7 +869,6 @@ CONFIG_FEATURE_TFTP_PROGRESS_BAR=y
 CONFIG_TRACEROUTE=y
 # CONFIG_TRACEROUTE6 is not set
 CONFIG_FEATURE_TRACEROUTE_VERBOSE=y
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 CONFIG_TUNCTL=y
 CONFIG_FEATURE_TUNCTL_UG=y
diff --git a/configs/cygwin_defconfig b/configs/cygwin_defconfig
index 38d580ad1..dd7c21edb 100644
--- a/configs/cygwin_defconfig
+++ b/configs/cygwin_defconfig
@@ -814,7 +814,6 @@ CONFIG_FEATURE_TFTP_PROGRESS_BAR=y
 # CONFIG_TRACEROUTE is not set
 # CONFIG_TRACEROUTE6 is not set
 # CONFIG_FEATURE_TRACEROUTE_VERBOSE is not set
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 # CONFIG_TUNCTL is not set
 # CONFIG_FEATURE_TUNCTL_UG is not set
diff --git a/configs/freebsd_defconfig b/configs/freebsd_defconfig
index ae62f1389..265ab1307 100644
--- a/configs/freebsd_defconfig
+++ b/configs/freebsd_defconfig
@@ -795,7 +795,6 @@ CONFIG_FEATURE_TFTP_PROGRESS_BAR=y
 # CONFIG_TRACEROUTE is not set
 # CONFIG_TRACEROUTE6 is not set
 # CONFIG_FEATURE_TRACEROUTE_VERBOSE is not set
-# CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
 # CONFIG_TUNCTL is not set
 # CONFIG_FEATURE_TUNCTL_UG is not set
diff --git a/networking/Config.src b/networking/Config.src
index 27c604a31..eb0536a7c 100644
--- a/networking/Config.src
+++ b/networking/Config.src
@@ -912,17 +912,9 @@ config FEATURE_TRACEROUTE_VERBOSE
           Add some verbosity to traceroute. This includes among other things
           hostnames and ICMP response types.
 
-config FEATURE_TRACEROUTE_SOURCE_ROUTE
-        bool "Enable loose source route"
-        default n
-        depends on TRACEROUTE
-        help
-          Add option to specify a loose source route gateway
-          (8 maximum).
-
 config FEATURE_TRACEROUTE_USE_ICMP
-        bool "Use ICMP instead of UDP"
-        default n
+        bool "Enable -I option (use ICMP instead of UDP)"
+        default y
         depends on TRACEROUTE
         help
           Add option -I to use ICMP ECHO instead of UDP datagrams.
diff --git a/networking/traceroute.c b/networking/traceroute.c
index e43a36dc7..b9a9ca4bb 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -212,8 +212,7 @@
 
 //usage:#define traceroute_trivial_usage
 //usage:       "[-"IF_TRACEROUTE6("46")"FIlnrv] [-f 1ST_TTL] [-m MAXTTL] [-q PROBES] [-p PORT]\n"
-//usage:       "        [-t TOS] [-w WAIT_SEC]"
-//usage:       IF_FEATURE_TRACEROUTE_SOURCE_ROUTE(" [-g GATEWAY]")" [-s SRC_IP] [-i IFACE]\n"
+//usage:       "        [-t TOS] [-w WAIT_SEC] [-s SRC_IP] [-i IFACE]\n"
 //usage:       "        [-z PAUSE_MSEC] HOST [BYTES]"
 //usage:#define traceroute_full_usage "\n\n"
 //usage:       "Trace the route to HOST\n"
@@ -294,7 +293,6 @@
 
 #define OPT_STRING \
         "FIlnrdvxt:i:m:p:q:s:w:z:f:" \
-        IF_FEATURE_TRACEROUTE_SOURCE_ROUTE("g:*") \
         "4" IF_TRACEROUTE6("6")
 enum {
         OPT_DONT_FRAGMNT = (1 << 0),    /* F */
@@ -314,9 +312,8 @@ enum {
         OPT_WAITTIME     = (1 << 14),   /* w */
         OPT_PAUSE_MS     = (1 << 15),   /* z */
         OPT_FIRST_TTL    = (1 << 16),   /* f */
-        OPT_SOURCE_ROUTE = (1 << 17) * ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE, /* g */
-        OPT_IPV4         = (1 << (17+ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE)),   /* 4 */
-        OPT_IPV6         = (1 << (18+ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE)) * ENABLE_TRACEROUTE6, /* 6 */
+        OPT_IPV4         = (1 << 17),   /* 4 */
+        OPT_IPV6         = (1 << 18) * ENABLE_TRACEROUTE6, /* 6 */
 };
 #define verbose (option_mask32 & OPT_VERBOSE)
 
@@ -343,26 +340,18 @@ struct outdata6_t {
 #endif
 
 struct globals {
+        /* Pointer to entire malloced IP packet, "packlen" bytes long: */
         struct ip *outip;
+        /* Pointer to ICMP or UDP payload (not header): */
         struct outdata_t *outdata;
+
         len_and_sockaddr *dest_lsa;
         int packlen;                    /* total length of packet */
         int pmtu;                       /* Path MTU Discovery (RFC1191) */
         uint32_t ident;
-        uint16_t port; // 32768 + 666;  /* start udp dest port # for probe packets */
+        uint16_t port; // 33434;        /* start udp dest port # for probe packets */
         int waittime; // 5;             /* time to wait for response (in seconds) */
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
-        int optlen;                     /* length of ip options */
-#else
-#define optlen 0
-#endif
         unsigned char recv_pkt[512];    /* last inbound (icmp) packet */
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
-        /* Maximum number of gateways (include room for one noop) */
-#define NGATEWAYS ((int)((MAX_IPOPTLEN - IPOPT_MINOFF - 1) / sizeof(uint32_t)))
-        /* loose source route gateway list (including room for final destination) */
-        uint32_t gwlist[NGATEWAYS + 1];
-#endif
 };
 
 #define G (*ptr_to_globals)
@@ -374,14 +363,11 @@ struct globals {
 #define ident     (G.ident    )
 #define port      (G.port     )
 #define waittime  (G.waittime )
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
-# define optlen   (G.optlen   )
-#endif
 #define recv_pkt  (G.recv_pkt )
 #define gwlist    (G.gwlist   )
 #define INIT_G() do { \
         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
-        port = 32768 + 666; \
+        port = 33434; \
         waittime = 5; \
 } while (0)
 
@@ -421,7 +407,7 @@ send_probe(int seq, int ttl)
         /* Payload */
 #if ENABLE_TRACEROUTE6
         if (dest_lsa->u.sa.sa_family == AF_INET6) {
-                struct outdata6_t *pkt = (struct outdata6_t *) outip;
+                struct outdata6_t *pkt = (struct outdata6_t *) outdata;
                 pkt->ident6 = htonl(ident);
                 pkt->seq6   = htonl(seq);
                 /*gettimeofday(&pkt->tv, &tz);*/
@@ -438,8 +424,10 @@ send_probe(int seq, int ttl)
 
                         /* Always calculate checksum for icmp packets */
                         outicmp->icmp_cksum = 0;
-                        outicmp->icmp_cksum = inet_cksum((uint16_t *)outicmp,
-                                                packlen - (sizeof(*outip) + optlen));
+                        outicmp->icmp_cksum = inet_cksum(
+                                        (uint16_t *)outicmp,
+                                        ((char*)outip + packlen) - (char*)outicmp
+                        );
                         if (outicmp->icmp_cksum == 0)
                                 outicmp->icmp_cksum = 0xffff;
                 }
@@ -471,13 +459,12 @@ send_probe(int seq, int ttl)
         }
 #endif
 
+        out = outdata;
 #if ENABLE_TRACEROUTE6
         if (dest_lsa->u.sa.sa_family == AF_INET6) {
                 res = setsockopt_int(sndsock, SOL_IPV6, IPV6_UNICAST_HOPS, ttl);
                 if (res != 0)
                         bb_perror_msg_and_die("setsockopt(%s) %d", "UNICAST_HOPS", ttl);
-                out = outip;
-                len = packlen;
         } else
 #endif
         {
@@ -486,15 +473,14 @@ send_probe(int seq, int ttl)
                 if (res != 0)
                         bb_perror_msg_and_die("setsockopt(%s) %d", "TTL", ttl);
 #endif
-                out = outicmp;
-                len = packlen - sizeof(*outip);
-                if (!(option_mask32 & OPT_USE_ICMP)) {
-                        out = outdata;
-                        len -= sizeof(*outudp);
-                        set_nport(&dest_lsa->u.sa, htons(port + seq));
-                }
+                if (option_mask32 & OPT_USE_ICMP)
+                        out = outicmp;
         }
 
+        if (!(option_mask32 & OPT_USE_ICMP)) {
+                set_nport(&dest_lsa->u.sa, htons(port + seq));
+        }
+        len = ((char*)outip + packlen) - (char*)out;
         res = xsendto(sndsock, out, len, &dest_lsa->u.sa, dest_lsa->len);
         if (res != len)
                 bb_error_msg("sent %d octets, ret=%d", len, res);
@@ -801,10 +787,6 @@ common_traceroute_main(int op, char **argv)
         char *pausemsecs_str;
         char *first_ttl_str;
         char *dest_str;
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
-        llist_t *source_route_list = NULL;
-        int lsrr = 0;
-#endif
 #if ENABLE_TRACEROUTE6
         sa_family_t af;
 #else
@@ -823,9 +805,6 @@ common_traceroute_main(int op, char **argv)
         op |= getopt32(argv, OPT_STRING
                 , &tos_str, &device, &max_ttl_str, &port_str, &nprobes_str
                 , &source, &waittime_str, &pausemsecs_str, &first_ttl_str
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
-                , &source_route_list
-#endif
         );
         argv += optind;
 
@@ -858,26 +837,14 @@ common_traceroute_main(int op, char **argv)
         if (op & OPT_FIRST_TTL)
                 first_ttl = xatou_range(first_ttl_str, 1, max_ttl);
 
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
-        if (source_route_list) {
-                while (source_route_list) {
-                        len_and_sockaddr *lsa;
-
-                        if (lsrr >= NGATEWAYS)
-                                bb_error_msg_and_die("no more than %d gateways", NGATEWAYS);
-                        lsa = xhost_and_af2sockaddr(llist_pop(&source_route_list), 0, AF_INET);
-                        gwlist[lsrr] = lsa->u.sin.sin_addr.s_addr;
-                        free(lsa);
-                        ++lsrr;
-                }
-                optlen = (lsrr + 1) * sizeof(gwlist[0]);
-        }
-#endif
-
         /* Process destination and optional packet size */
-        minpacket = sizeof(*outip) + SIZEOF_ICMP_HDR + sizeof(*outdata) + optlen;
+        minpacket = sizeof(struct ip)
+                        + SIZEOF_ICMP_HDR
+                        + sizeof(struct outdata_t);
         if (!(op & OPT_USE_ICMP))
-                minpacket += sizeof(*outudp) - SIZEOF_ICMP_HDR;
+                minpacket = sizeof(struct ip)
+                        + sizeof(struct udphdr)
+                        + sizeof(struct outdata_t);
 #if ENABLE_TRACEROUTE6
         af = AF_UNSPEC;
         if (op & OPT_IPV4)
@@ -887,7 +854,9 @@ common_traceroute_main(int op, char **argv)
         dest_lsa = xhost_and_af2sockaddr(argv[0], port, af);
         af = dest_lsa->u.sa.sa_family;
         if (af == AF_INET6)
-                minpacket = sizeof(struct outdata6_t);
+                minpacket = sizeof(struct ip6_hdr)
+                        + sizeof(struct udphdr)
+                        + sizeof(struct outdata6_t);
 #else
         dest_lsa = xhost2sockaddr(argv[0], port);
 #endif
@@ -932,31 +901,6 @@ common_traceroute_main(int op, char **argv)
                         xmove_fd(xsocket(AF_INET, SOCK_RAW, IPPROTO_ICMP), sndsock);
                 else
                         xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sndsock);
-#if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE && defined IP_OPTIONS
-                if (lsrr > 0) {
-                        unsigned char optlist[MAX_IPOPTLEN];
-                        unsigned size;
-
-                        /* final hop */
-                        gwlist[lsrr] = dest_lsa->u.sin.sin_addr.s_addr;
-                        ++lsrr;
-
-                        /* force 4 byte alignment */
-                        optlist[0] = IPOPT_NOP;
-                        /* loose source route option */
-                        optlist[1] = IPOPT_LSRR;
-                        size = lsrr * sizeof(gwlist[0]);
-                        optlist[2] = size + 3;
-                        /* pointer to LSRR addresses */
-                        optlist[3] = IPOPT_MINOFF;
-                        memcpy(optlist + 4, gwlist, size);
-
-                        if (setsockopt(sndsock, IPPROTO_IP, IP_OPTIONS,
-                                        (char *)optlist, size + sizeof(gwlist[0])) < 0) {
-                                bb_perror_msg_and_die("IP_OPTIONS");
-                        }
-                }
-#endif
         }
 
 #ifdef SO_SNDBUF
@@ -984,7 +928,7 @@ common_traceroute_main(int op, char **argv)
 
         ident = getpid();
 
-        if (af == AF_INET) {
+        if (!ENABLE_TRACEROUTE6 || af == AF_INET) {
                 if (op & OPT_USE_ICMP) {
                         ident |= 0x8000;
                         outicmp->icmp_type = ICMP_ECHO;
@@ -994,6 +938,14 @@ common_traceroute_main(int op, char **argv)
                         outdata = (struct outdata_t *)(outudp + 1);
                 }
         }
+#if ENABLE_TRACEROUTE6
+        if (af == AF_INET6) {
+                outdata = (void*)((char*)outip
+                                + sizeof(struct ip6_hdr)
+                                + sizeof(struct udphdr)
+                                );
+        }
+#endif
 
         if (op & OPT_DEVICE) /* hmm, do we need error check? */
                 setsockopt_bindtodevice(sndsock, device);