eliminate aliasing warnings in traceroute.c and udhcp/socket.c

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

2 files changed, 16 insertions, 12 deletions

diff --git a/networking/traceroute.c b/networking/traceroute.c
index c18fba8d0..82bb0118c 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -751,7 +751,8 @@ print(int read_len, const struct sockaddr *from, const struct sockaddr *to)
                 } else
 #endif
                 {
-                        read_len -= ((struct ip*)recv_pkt)->ip_hl << 2;
+                        struct ip *ip4packet = (struct ip*)recv_pkt;
+                        read_len -= ip4packet->ip_hl << 2;
                 }
                 printf(" %d bytes to %s", read_len, ina);
                 free(ina);
diff --git a/networking/udhcp/socket.c b/networking/udhcp/socket.c
index 0ed7ad1c6..39f1cec54 100644
--- a/networking/udhcp/socket.c
+++ b/networking/udhcp/socket.c
@@ -36,42 +36,45 @@
 
 int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac)
 {
+        /* char buffer instead of bona-fide struct avoids aliasing warning */
+        char ifr_buf[sizeof(struct ifreq)];
+        struct ifreq *const ifr = (void *)ifr_buf;
+
         int fd;
-        struct ifreq ifr;
         struct sockaddr_in *our_ip;
 
-        memset(&ifr, 0, sizeof(ifr));
+        memset(ifr, 0, sizeof(*ifr));
         fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
 
-        ifr.ifr_addr.sa_family = AF_INET;
-        strncpy_IFNAMSIZ(ifr.ifr_name, interface);
+        ifr->ifr_addr.sa_family = AF_INET;
+        strncpy_IFNAMSIZ(ifr->ifr_name, interface);
         if (nip) {
-                if (ioctl_or_perror(fd, SIOCGIFADDR, &ifr,
+                if (ioctl_or_perror(fd, SIOCGIFADDR, ifr,
                         "is interface %s up and configured?", interface)
                 ) {
                         close(fd);
                         return -1;
                 }
-                our_ip = (struct sockaddr_in *) &ifr.ifr_addr;
+                our_ip = (struct sockaddr_in *) &ifr->ifr_addr;
                 *nip = our_ip->sin_addr.s_addr;
                 log1("IP %s", inet_ntoa(our_ip->sin_addr));
         }
 
         if (ifindex) {
-                if (ioctl_or_warn(fd, SIOCGIFINDEX, &ifr) != 0) {
+                if (ioctl_or_warn(fd, SIOCGIFINDEX, ifr) != 0) {
                         close(fd);
                         return -1;
                 }
-                log1("Adapter index %d", ifr.ifr_ifindex);
-                *ifindex = ifr.ifr_ifindex;
+                log1("Adapter index %d", ifr->ifr_ifindex);
+                *ifindex = ifr->ifr_ifindex;
         }
 
         if (mac) {
-                if (ioctl_or_warn(fd, SIOCGIFHWADDR, &ifr) != 0) {
+                if (ioctl_or_warn(fd, SIOCGIFHWADDR, ifr) != 0) {
                         close(fd);
                         return -1;
                 }
-                memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
+                memcpy(mac, ifr->ifr_hwaddr.sa_data, 6);
                 log1("MAC %02x:%02x:%02x:%02x:%02x:%02x",
                         mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
         }