diff --git a/ndhc/arp.c b/ndhc/arp.c
index ac866f1..8e65ce8 100644
--- a/ndhc/arp.c
+++ b/ndhc/arp.c
@@ -709,7 +709,7 @@ static const arp_state_fn_t arp_states[] = {
 
 void handle_arp_response(struct client_state_t *cs)
 {
-    int r = 0;
+    ssize_t r = 0;
     if (arpreply_offset < sizeof arpreply) {
         r = safe_read(cs->arpFd, (char *)&arpreply + arpreply_offset,
                       sizeof arpreply - arpreply_offset);
@@ -721,7 +721,7 @@ void handle_arp_response(struct client_state_t *cs)
             default: arp_reopen_fd(cs); break;
             }
         } else
-            arpreply_offset += r;
+            arpreply_offset += (size_t)r;
     }
 
     if (r <= 0) {
diff --git a/ndhc/dhcp.c b/ndhc/dhcp.c
index 97c0169..44df7cb 100644
--- a/ndhc/dhcp.c
+++ b/ndhc/dhcp.c
@@ -86,9 +86,10 @@ static int get_raw_listen_socket(struct client_state_t *cs)
 }
 
 // Broadcast a DHCP message using a UDP socket.
-static int send_dhcp_cooked(struct client_state_t *cs, struct dhcpmsg *payload)
+static ssize_t send_dhcp_cooked(struct client_state_t *cs,
+                                struct dhcpmsg *payload)
 {
-    int ret = -1;
+    ssize_t ret = -1;
     int fd = get_udp_unicast_socket();
     if (fd == -1)
         goto out;
@@ -125,11 +126,11 @@ static int send_dhcp_cooked(struct client_state_t *cs, struct dhcpmsg *payload)
 
 // Read a packet from a cooked socket.  Returns -1 on fatal error, -2 on
 // transient error.
-static int get_cooked_packet(struct dhcpmsg *packet, int fd)
+static ssize_t get_cooked_packet(struct dhcpmsg *packet, int fd)
 {
     memset(packet, 0, sizeof *packet);
-    int bytes = safe_read(fd, (char *)packet, sizeof *packet);
-    if (bytes == -1) {
+    ssize_t bytes = safe_read(fd, (char *)packet, sizeof *packet);
+    if (bytes < 0) {
         if (errno == EAGAIN || errno == EWOULDBLOCK)
             return -2;
         log_line("%s: Read on listen socket failed: %s",
@@ -237,13 +238,14 @@ static int get_raw_packet_validate_bpf(struct ip_udp_dhcp_packet *packet)
 
 // Read a packet from a raw socket.  Returns -1 on fatal error, -2 on
 // transient error.
-static int get_raw_packet(struct client_state_t *cs, struct dhcpmsg *payload)
+static ssize_t get_raw_packet(struct client_state_t *cs,
+                              struct dhcpmsg *payload)
 {
     struct ip_udp_dhcp_packet packet;
     memset(&packet, 0, sizeof packet);
 
     ssize_t inc = safe_read(cs->listenFd, (char *)&packet, sizeof packet);
-    if (inc == -1) {
+    if (inc < 0) {
         if (errno == EAGAIN || errno == EWOULDBLOCK)
             return -2;
         log_warning("%s: (%s) read error %s", client_config.interface,
@@ -277,9 +279,9 @@ static int get_raw_packet(struct client_state_t *cs, struct dhcpmsg *payload)
 }
 
 // Broadcast a DHCP message using a raw socket.
-static int send_dhcp_raw(struct dhcpmsg *payload)
+static ssize_t send_dhcp_raw(struct dhcpmsg *payload)
 {
-    int ret = -1;
+    ssize_t ret = -1;
     int fd = get_raw_broadcast_socket();
     if (fd == -1)
         return ret;
@@ -333,7 +335,7 @@ static int send_dhcp_raw(struct dhcpmsg *payload)
     memcpy(da.sll_addr, "\xff\xff\xff\xff\xff\xff", 6);
     ret = safe_sendto(fd, (const char *)&iudmsg, iud_len, 0,
                       (struct sockaddr *)&da, sizeof da);
-    if (ret == -1)
+    if (ret < 0)
         log_error("%s: (%s) sendto failed: %s", client_config.interface,
                   __func__, strerror(errno));
     close(fd);
@@ -429,7 +431,7 @@ void handle_packet(struct client_state_t *cs)
 
     if (cs->listenMode == LM_NONE)
         return;
-    int r = cs->listenMode == LM_RAW ?
+    ssize_t r = cs->listenMode == LM_RAW ?
         get_raw_packet(cs, &packet) : get_cooked_packet(&packet, cs->listenFd);
     if (r < 0) {
         // Transient issue handled by packet collection functions.
@@ -465,7 +467,7 @@ static struct dhcpmsg init_packet(char type, uint32_t xid)
     return packet;
 }
 
-int send_discover(struct client_state_t *cs)
+ssize_t send_discover(struct client_state_t *cs)
 {
     struct dhcpmsg packet = init_packet(DHCPDISCOVER, cs->xid);
     if (cs->clientAddr)
@@ -478,7 +480,7 @@ int send_discover(struct client_state_t *cs)
     return send_dhcp_raw(&packet);
 }
 
-int send_selecting(struct client_state_t *cs)
+ssize_t send_selecting(struct client_state_t *cs)
 {
     char clibuf[INET_ADDRSTRLEN];
     struct dhcpmsg packet = init_packet(DHCPREQUEST, cs->xid);
@@ -495,7 +497,7 @@ int send_selecting(struct client_state_t *cs)
     return send_dhcp_raw(&packet);
 }
 
-int send_renew(struct client_state_t *cs)
+ssize_t send_renew(struct client_state_t *cs)
 {
     struct dhcpmsg packet = init_packet(DHCPREQUEST, cs->xid);
     packet.ciaddr = cs->clientAddr;
@@ -507,7 +509,7 @@ int send_renew(struct client_state_t *cs)
     return send_dhcp_cooked(cs, &packet);
 }
 
-int send_rebind(struct client_state_t *cs)
+ssize_t send_rebind(struct client_state_t *cs)
 {
     struct dhcpmsg packet = init_packet(DHCPREQUEST, cs->xid);
     packet.ciaddr = cs->clientAddr;
@@ -520,7 +522,7 @@ int send_rebind(struct client_state_t *cs)
     return send_dhcp_raw(&packet);
 }
 
-int send_decline(struct client_state_t *cs, uint32_t server)
+ssize_t send_decline(struct client_state_t *cs, uint32_t server)
 {
     struct dhcpmsg packet = init_packet(DHCPDECLINE, cs->xid);
     add_option_reqip(&packet, cs->clientAddr);
@@ -529,7 +531,7 @@ int send_decline(struct client_state_t *cs, uint32_t server)
     return send_dhcp_raw(&packet);
 }
 
-int send_release(struct client_state_t *cs)
+ssize_t send_release(struct client_state_t *cs)
 {
     struct dhcpmsg packet = init_packet(DHCPRELEASE,
                                         nk_random_u32(&cs->rnd32_state));
diff --git a/ndhc/dhcp.h b/ndhc/dhcp.h
index 8bbdbbf..b674386 100644
--- a/ndhc/dhcp.h
+++ b/ndhc/dhcp.h
@@ -85,11 +85,11 @@ void set_listen_raw(struct client_state_t *cs);
 void set_listen_cooked(struct client_state_t *cs);
 void set_listen_none(struct client_state_t *cs);
 void handle_packet(struct client_state_t *cs);
-int send_discover(struct client_state_t *cs);
-int send_selecting(struct client_state_t *cs);
-int send_renew(struct client_state_t *cs);
-int send_rebind(struct client_state_t *cs);
-int send_decline(struct client_state_t *cs, uint32_t server);
-int send_release(struct client_state_t *cs);
+ssize_t send_discover(struct client_state_t *cs);
+ssize_t send_selecting(struct client_state_t *cs);
+ssize_t send_renew(struct client_state_t *cs);
+ssize_t send_rebind(struct client_state_t *cs);
+ssize_t send_decline(struct client_state_t *cs, uint32_t server);
+ssize_t send_release(struct client_state_t *cs);
 
 #endif
diff --git a/ndhc/duiaid.c b/ndhc/duiaid.c
index 5d37090..4ecbb28 100644
--- a/ndhc/duiaid.c
+++ b/ndhc/duiaid.c
@@ -169,15 +169,16 @@ void get_clientid(struct client_state_t *cs, struct client_config_t *cc)
     if (fd < 0) {
         iaid_len = generate_iaid(&cs->rnd32_state, iaid, sizeof iaid);
         fd = open_iaidfile_write(cc->arp, sizeof cc->arp);
-        int r = safe_write(fd, iaid, iaid_len);
+        ssize_t r = safe_write(fd, iaid, iaid_len);
         if (r < 0 || (size_t)r != iaid_len)
             suicide("%s: (%s) failed to write generated IAID.",
                     cc->interface, __func__);
     } else {
-        iaid_len = safe_read(fd, iaid, sizeof iaid);
-        if (iaid_len < 0)
+        ssize_t r = safe_read(fd, iaid, sizeof iaid);
+        if (r < 0)
             suicide("%s: (%s) failed to read IAID from file",
                     cc->interface, __func__);
+        iaid_len = (size_t)r;
     }
     close(fd);
 
@@ -185,15 +186,16 @@ void get_clientid(struct client_state_t *cs, struct client_config_t *cc)
     if (fd < 0) {
         duid_len = generate_duid(&cs->rnd32_state, duid, sizeof duid);
         fd = open_duidfile_write();
-        int r = safe_write(fd, duid, duid_len);
+        ssize_t r = safe_write(fd, duid, duid_len);
         if (r < 0 || (size_t)r != duid_len)
             suicide("%s: (%s) failed to write generated DUID.",
                     cc->interface, __func__);
     } else {
-        duid_len = safe_read(fd, duid, sizeof duid);
-        if (duid_len < 0)
+        ssize_t r = safe_read(fd, duid, sizeof duid);
+        if (r < 0)
             suicide("%s: (%s) failed to read DUID from file",
                     cc->interface, __func__);
+        duid_len = (size_t)r;
     }
     close(fd);
 
diff --git a/ndhc/ifchange.c b/ndhc/ifchange.c
index ea6a8d9..53afd79 100644
--- a/ndhc/ifchange.c
+++ b/ndhc/ifchange.c
@@ -187,7 +187,7 @@ static int ifchd_cmd(char *b, size_t bl, uint8_t *od, ssize_t ol, uint8_t code)
 static void pipewrite(struct client_state_t *cs, const char *buf, size_t count)
 {
     cs->ifchWorking = 1;
-    int r = safe_write(pToIfchW, buf, count);
+    ssize_t r = safe_write(pToIfchW, buf, count);
     if (r < 0 || (size_t)r != count) {
         log_error("%s: (%s) write failed: %d", client_config.interface);
         return;
diff --git a/ndhc/leasefile.c b/ndhc/leasefile.c
index 45c44ad..a609e2e 100644
--- a/ndhc/leasefile.c
+++ b/ndhc/leasefile.c
@@ -70,7 +70,7 @@ void write_leasefile(struct in_addr ipnum)
 {
     char ip[INET_ADDRSTRLEN];
     char out[INET_ADDRSTRLEN*2];
-    int ret;
+    ssize_t ret;
     if (leasefilefd < 0) {
         log_error("%s: (%s) leasefile fd < 0; no leasefile will be written",
                   client_config.interface, __func__);
diff --git a/ndhc/ndhc.c b/ndhc/ndhc.c
index feb5fe8..21b5c39 100644
--- a/ndhc/ndhc.c
+++ b/ndhc/ndhc.c
@@ -241,7 +241,7 @@ static void fail_if_state_dir_dne(void)
 static void handle_ifch_message(void)
 {
     char c;
-    int r = safe_read(pToNdhcR, &c, sizeof c);
+    ssize_t r = safe_read(pToNdhcR, &c, sizeof c);
     if (r == 0) {
         // Remote end hung up.
         exit(EXIT_SUCCESS);