passt: Add cppcheck target, test, and address resulting warnings

...mostly false positives, but a number of very relevant ones too,
in tcp_get_sndbuf(), tcp_conn_from_tap(), and siphash PREAMBLE().

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Makefile

@@ -141,7 +141,7 @@ pkgs:
 #
 # - bugprone-suspicious-string-compare
 #	Return value of memcmp(), not really suspicious
-clang-tidy: $(wildcard *.c)
+clang-tidy: $(wildcard *.c) $(wildcard *.h)
 	clang-tidy -checks=*,-modernize-*,\
 	-clang-analyzer-valist.Uninitialized,\
 	-cppcoreguidelines-init-variables,\
@@ -163,3 +163,33 @@ clang-tidy: $(wildcard *.c)
 	-cppcoreguidelines-avoid-non-const-global-variables,\
 	-bugprone-suspicious-string-compare \
 	--warnings-as-errors=* $(wildcard *.c) -- $(CFLAGS)
+
+ifeq ($(shell $(CC) -v 2>&1 | grep -c "gcc version"),1)
+TARGET := $(shell ${CC} -v 2>&1 | sed -n 's/Target: \(.*\)/\1/p')
+VER := $(shell $(CC) -dumpversion)
+EXTRA_INCLUDES := /usr/lib/gcc/$(TARGET)/$(VER)/include
+EXTRA_INCLUDES_OPT := -I$(EXTRA_INCLUDES)
+else
+EXTRA_INCLUDES_OPT :=
+endif
+cppcheck: $(wildcard *.c) $(wildcard *.h)
+	cppcheck --std=c99 --error-exitcode=1 --enable=all --force	\
+	--inconclusive --library=posix					\
+	-I/usr/include $(EXTRA_INCLUDES_OPT)				\
+	--suppress=missingIncludeSystem					\
+	--suppress="*:$(EXTRA_INCLUDES)/avx512fintrin.h"		\
+	--suppress="*:$(EXTRA_INCLUDES)/xmmintrin.h"			\
+	--suppress="*:$(EXTRA_INCLUDES)/emmintrin.h"			\
+	--suppress="*:$(EXTRA_INCLUDES)/avxintrin.h"			\
+	--suppress="*:$(EXTRA_INCLUDES)/bmiintrin.h"			\
+	--suppress=objectIndex:tcp.c --suppress=objectIndex:udp.c	\
+	--suppress=va_list_usedBeforeStarted:util.c			\
+	--suppress=unusedFunction:igmp.c				\
+	--suppress=unusedFunction:siphash.c				\
+	--suppress=knownConditionTrueFalse:conf.c			\
+	--suppress=strtokCalled:conf.c --suppress=strtokCalled:qrap.c	\
+	--suppress=getpwnamCalled:passt.c				\
+	--suppress=localtimeCalled:pcap.c				\
+	--suppress=unusedStructMember:pcap.c				\
+	--suppress=funcArgNamesDifferent:util.h				\
+	.

checksum.c

@@ -167,8 +167,8 @@ static uint32_t csum_avx2(const void *buf, size_t len, uint32_t init)
 {
 	__m256i a, b, sum256, sum_a_hi, sum_a_lo, sum_b_hi, sum_b_lo, c, d;
 	__m256i __sum_a_hi, __sum_a_lo, __sum_b_hi, __sum_b_lo;
-	const uint64_t *buf64 = (const uint64_t *)buf;
+	const __m256i *buf256 = (const __m256i *)buf;
-	const __m256i *buf256;
+	const uint64_t *buf64;
 	const uint16_t *buf16;
 	uint64_t sum64 = init;
 	int odd = len & 1;
@@ -176,7 +176,6 @@ static uint32_t csum_avx2(const void *buf, size_t len, uint32_t init)
 	__m256i zero;
 
 	zero = _mm256_setzero_si256();
-	buf256 = (const __m256i *)buf64;
 
 	if (len < sizeof(__m256i) * 4)
 		goto less_than_128_bytes;
@@ -267,7 +266,6 @@ static uint32_t csum_avx2(const void *buf, size_t len, uint32_t init)
 
 	/* Fold 128-bit sum into 64 bits. */
 	sum64 += _mm_extract_epi64(sum128, 0) + _mm_extract_epi64(sum128, 1);
-	buf64 = (const uint64_t *)buf256;
 
 less_than_128_bytes:
 	for (; len >= sizeof(a); len -= sizeof(a), buf256++) {

conf.c

@@ -678,7 +678,7 @@ pasta_opts:
 
 void conf_print(struct ctx *c)
 {
-	char buf6[INET6_ADDRSTRLEN], buf4[INET_ADDRSTRLEN], ifn[IFNAMSIZ];
+	char buf4[INET_ADDRSTRLEN], ifn[IFNAMSIZ];
 	int i;
 
 	if (c->mode == MODE_PASTA) {
@@ -723,6 +723,8 @@ void conf_print(struct ctx *c)
 	}
 
 	if (c->v6) {
+		char buf6[INET6_ADDRSTRLEN];
+
 		if (!c->no_ndp && !c->no_dhcpv6)
 			info("NDP/DHCPv6:");
 		else if (!c->no_ndp)
@@ -1013,7 +1015,7 @@ void conf(struct ctx *c, int argc, char **argv)
 
 			errno = 0;
 			mask = strtol(optarg, NULL, 0);
-			if (mask >= 0 && mask <= 32 && !errno) {
+			if (mask > 0 && mask <= 32 && !errno) {
 				c->mask4 = htonl(0xffffffff << (32 - mask));
 				break;
 			}

dhcp.c

@@ -212,19 +212,20 @@ static void opt_set_dns_search(struct ctx *c, size_t max_len)
 
 	for (i = 0; *c->dns_search[i].n; i++) {
 		unsigned int n;
-		int dup = -1;
+		int count = -1;
 		char *p;
 
 		buf[0] = 0;
 		for (p = c->dns_search[i].n, n = 1; *p; p++) {
 			if (*p == '.') {
 				/* RFC 1035 4.1.4 Message compression */
-				dup = opt_dns_search_dup_ptr(opts[119].s, p + 1,
+				count = opt_dns_search_dup_ptr(opts[119].s,
-							     opts[119].slen);
+							       p + 1,
+							       opts[119].slen);
 
-				if (dup >= 0) {
+				if (count >= 0) {
 					buf[n++] = '\xc0';
-					buf[n++] = dup;
+					buf[n++] = count;
 					break;
 				}
 				buf[n++] = '.';
@@ -234,7 +235,7 @@ static void opt_set_dns_search(struct ctx *c, size_t max_len)
 		}
 
 		/* The compression pointer is also an end of label */
-		if (dup < 0)
+		if (count < 0)
 			buf[n++] = 0;
 
 		if (n >= max_len)

ndp.c

@@ -91,7 +91,7 @@ int ndp(struct ctx *c, struct ethhdr *eh, size_t len)
 		memcpy(p, c->mac, ETH_ALEN);
 		p += 6;
 	} else if (ih->icmp6_type == RS) {
-		size_t len = 0;
+		size_t dns_s_len = 0;
 		int i, n;
 
 		if (c->no_ra)
@@ -139,7 +139,7 @@ int ndp(struct ctx *c, struct ethhdr *eh, size_t len)
 		}
 
 		for (n = 0; *c->dns_search[n].n; n++)
-			len += strlen(c->dns_search[n].n) + 2;
+			dns_s_len += strlen(c->dns_search[n].n) + 2;
 		if (len) {
 			*p++ = 31;			/* DNSSL */
 			*p++ = (len + 8 - 1) / 8 + 1;	/* length */
@@ -163,8 +163,8 @@ int ndp(struct ctx *c, struct ethhdr *eh, size_t len)
 				*(p++) = 0;
 			}
 
-			memset(p, 0, 8 - len % 8);	/* padding */
+			memset(p, 0, 8 - dns_s_len % 8);	/* padding */
-			p += 8 - len % 8;
+			p += 8 - dns_s_len % 8;
 		}
 
 		*p++ = 1;			/* source ll */

netlink.c

@@ -47,7 +47,6 @@ static int nl_seq;
 static int nl_sock_init_do(void *arg)
 {
 	struct sockaddr_nl addr = { .nl_family = AF_NETLINK, };
-	struct ctx *c = (struct ctx *)arg;
 	int *s = &nl_sock, v = 1;
 
 ns:
@@ -55,7 +54,7 @@ ns:
 	    bind(*s, (struct sockaddr *)&addr, sizeof(addr)))
 		*s = -1;
 
-	if (*s == -1 || !c || s == &nl_sock_ns)
+	if (*s == -1 || !arg || s == &nl_sock_ns)
 		return 0;
 
 	setsockopt(*s, SOL_NETLINK, NETLINK_GET_STRICT_CHK, &v, sizeof(v));
@@ -206,11 +205,10 @@ v6:
 
 	word = (long *)has_v4;
 	for (i = 0; i < ARRAY_SIZE(has_v4) / sizeof(long); i++, word++) {
-		int ifi;
-
 		tmp = *word;
 		while ((n = ffsl(tmp))) {
-			ifi = i * sizeof(long) * 8 + n - 1;
+			int ifi = i * sizeof(long) * 8 + n - 1;
+
 			if (!first_v4)
 				first_v4 = ifi;
 

passt.c

@@ -272,7 +272,7 @@ static void pid_file(struct ctx *c) {
  * @argc:	Argument count
  * @argv:	Options, plus optional target PID for pasta mode
  *
- * Return: 0 once interrupted, non-zero on failure
+ * Return: non-zero on failure
  *
  * #syscalls read write open close fork dup2 exit chdir ioctl writev syslog
  * #syscalls prlimit64 epoll_ctl epoll_create1 epoll_wait accept4 accept listen
@@ -394,6 +394,4 @@ loop:
 	post_handler(&c, &now);
 
 	goto loop;
-
-	return 0;
 }

passt.h

@@ -44,7 +44,7 @@ union epoll_ref;
  */
 union epoll_ref {
 	struct {
-		uint32_t	proto:8,
+		int32_t		proto:8,
 				s:24;
 		union {
 			union tcp_epoll_ref tcp;

pasta.c

@@ -167,9 +167,8 @@ netns:
  */
 void pasta_start_ns(struct ctx *c)
 {
-	char buf[BUFSIZ], *shell, proc_path[PATH_MAX];
+	int euid = geteuid(), fd;
-	int euid = geteuid();
+	char *shell;
-	int fd;
 
 	c->foreground = 1;
 	if (!c->debug)
@@ -181,6 +180,8 @@ void pasta_start_ns(struct ctx *c)
 	}
 
 	if (pasta_child_pid) {
+		char proc_path[PATH_MAX];
+
 		NS_CALL(pasta_wait_for_ns, c);
 
 		snprintf(proc_path, PATH_MAX, "/proc/%i/ns/net",
@@ -197,7 +198,9 @@ void pasta_start_ns(struct ctx *c)
 	}
 
 	if (!c->netns_only) {
-		snprintf(buf, BUFSIZ, "%u %u %u", 0, euid, 1);
+		char buf[BUFSIZ];
+
+		snprintf(buf, BUFSIZ, "%i %i %i", 0, euid, 1);
 
 		fd = open("/proc/self/uid_map", O_WRONLY);
 		if (write(fd, buf, strlen(buf)) < 0)

pcap.c

@@ -172,9 +172,7 @@ fail:
  */
 void pcap_init(struct ctx *c, int index)
 {
-	char name[] = PCAP_PREFIX PCAP_ISO8601_STR STR(UINT_MAX) ".pcap";
 	struct timeval tv;
-	struct tm *tm;
 
 	if (pcap_fd != -1)
 		return;
@@ -183,6 +181,10 @@ void pcap_init(struct ctx *c, int index)
 		return;
 
 	if (*c->pcap == 1) {
+		char name[] = PCAP_PREFIX PCAP_ISO8601_STR STR(UINT_MAX)
+			      ".pcap";
+		struct tm *tm;
+
 		if (c->mode == MODE_PASTA)
 			memcpy(name, PCAP_PREFIX_PASTA,
 			       sizeof(PCAP_PREFIX_PASTA));

qrap.c

@@ -127,7 +127,7 @@ int main(int argc, char **argv)
 		struct arphdr ah;
 		struct arpmsg am;
 	} probe = {
-		htonl(42),
+		.vnet_len = htonl(42),
 		{
 			.h_dest   = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 			.h_source = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
@@ -198,11 +198,12 @@ int main(int argc, char **argv)
 
 		if (!strcmp(argv[i], "-device") && i + 1 < argc) {
 			char *p;
-			long n;
 
 			has_dev = 1;
 
 			if ((p = strstr(argv[i + 1], dev->template))) {
+				long n;
+
 				n = strtol(p + strlen(dev->template), NULL, 16);
 				if (!errno)
 					addr_map |= (1 << n);

siphash.c

@@ -65,7 +65,7 @@
 	int __i;							  \
 									  \
 	do {								  \
-		for (__i = sizeof(v) / sizeof(v[0]); __i >= 0; __i--)	  \
+		for (__i = sizeof(v) / sizeof(v[0]) - 1; __i >= 0; __i--) \
 			v[__i] = k[__i % 2];				  \
 	} while (0)
 
@@ -152,13 +152,13 @@ __attribute__((__noinline__))	/* See comment in Makefile */
 uint64_t siphash_20b(const uint8_t *in, const uint64_t *k)
 {
 	uint32_t *in32 = (uint32_t *)in;
-	uint64_t combined;
 	int i;
 
 	PREAMBLE(20);
 
 	for (i = 0; i < 2; i++, in32 += 2) {
-		combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+		uint64_t combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+
 		v[3] ^= combined;
 		SIPROUND(2);
 		v[0] ^= combined;
@@ -205,13 +205,13 @@ uint32_t siphash_32b(const uint8_t *in, const uint64_t *k)
 uint32_t siphash_36b(const uint8_t *in, const uint64_t *k)
 {
 	uint32_t *in32 = (uint32_t *)in;
-	uint64_t combined;
 	int i;
 
 	PREAMBLE(36);
 
 	for (i = 0; i < 4; i++, in32 += 2) {
-		combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+		uint64_t combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+
 		v[3] ^= combined;
 		SIPROUND(2);
 		v[0] ^= combined;

tap.c

@@ -265,19 +265,22 @@ static void tap_packet_debug(struct iphdr *iph, struct ipv6hdr *ip6h,
 {
 	char buf6s[INET6_ADDRSTRLEN], buf6d[INET6_ADDRSTRLEN];
 	char buf4s[INET_ADDRSTRLEN], buf4d[INET_ADDRSTRLEN];
-	uint8_t proto;
+	uint8_t proto = 0;
 
 	if (iph || seq4) {
 		inet_ntop(AF_INET,   iph ? &iph->saddr  : &seq4->saddr,
-			  buf4s, sizeof(buf4s)),
+			  buf4s, sizeof(buf4s));
 		inet_ntop(AF_INET,   iph ? &iph->daddr  : &seq4->daddr,
-			  buf4d, sizeof(buf4d)),
+			  buf4d, sizeof(buf4d));
-		proto = iph ? iph->protocol : seq4->protocol;
+		if (iph)
+			proto = iph->protocol;
+		else if (seq4)
+			proto = seq4->protocol;
 	} else {
 		inet_ntop(AF_INET6, ip6h ? &ip6h->saddr : &seq6->saddr,
-			  buf6s, sizeof(buf6s)),
+			  buf6s, sizeof(buf6s));
 		inet_ntop(AF_INET6, ip6h ? &ip6h->daddr : &seq6->daddr,
-			  buf6d, sizeof(buf6d)),
+			  buf6d, sizeof(buf6d));
 		proto = proto6;
 	}
 
@@ -397,12 +400,12 @@ resume:
 		for (seq = l4_seq4 + seq_count - 1; seq >= l4_seq4; seq--) {
 			if (L4_MATCH(iph, uh, seq)) {
 				if (seq->msgs >= UIO_MAXIOV)
-					seq = l4_seq4 - 1;
+					seq = NULL;
 				break;
 			}
 		}
 
-		if (seq < l4_seq4) {
+		if (!seq || seq < l4_seq4) {
 			seq = l4_seq4 + seq_count++;
 			L4_SET(iph, uh, seq);
 			seq->msgs = 0;
@@ -560,12 +563,12 @@ resume:
 		for (seq = l4_seq6 + seq_count - 1; seq >= l4_seq6; seq--) {
 			if (L4_MATCH(ip6h, proto, uh, seq)) {
 				if (seq->msgs >= UIO_MAXIOV)
-					seq = l4_seq6 - 1;
+					seq = NULL;
 				break;
 			}
 		}
 
-		if (seq < l4_seq6) {
+		if (!seq || seq < l4_seq6) {
 			seq = l4_seq6 + seq_count++;
 			L4_SET(ip6h, proto, uh, seq);
 			seq->msgs = 0;
@@ -711,7 +714,7 @@ next:
 static int tap_handler_pasta(struct ctx *c, struct timespec *now)
 {
 	ssize_t n = 0, len;
-	int err, seq4_i = 0, seq6_i = 0;
+	int ret, seq4_i = 0, seq6_i = 0;
 
 restart:
 	while ((len = read(c->fd_tap, pkt_buf + n, TAP_BUF_BYTES - n)) > 0) {
@@ -749,7 +752,7 @@ restart:
 	if (len < 0 && errno == EINTR)
 		goto restart;
 
-	err = errno;
+	ret = errno;
 
 	if (seq4_i)
 		tap4_handler(c, seq4, seq4_i, now);
@@ -757,7 +760,7 @@ restart:
 	if (seq6_i)
 		tap6_handler(c, seq6, seq6_i, now);
 
-	if (len > 0 || err == EAGAIN)
+	if (len > 0 || ret == EAGAIN)
 		return 0;
 
 	epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_tap, NULL);

tcp.c

@@ -757,13 +757,14 @@ static int tcp_rtt_dst_low(struct tcp_tap_conn *conn)
 /**
  * tcp_rtt_dst_check() - Check tcpi_min_rtt, insert endpoint in table if low
  * @conn:	Connection pointer
- * @info:	Pointer to struct tcp_info for socket
+ * @tinfo:	Pointer to struct tcp_info for socket
  */
-static void tcp_rtt_dst_check(struct tcp_tap_conn *conn, struct tcp_info *info)
+static void tcp_rtt_dst_check(struct tcp_tap_conn *conn, struct tcp_info *tinfo)
 {
 	int i, hole = -1;
 
-	if (!info->tcpi_min_rtt || (int)info->tcpi_min_rtt > LOW_RTT_THRESHOLD)
+	if (!tinfo->tcpi_min_rtt ||
+	    (int)tinfo->tcpi_min_rtt > LOW_RTT_THRESHOLD)
 		return;
 
 	for (i = 0; i < LOW_RTT_TABLE_SIZE; i++) {
@@ -809,21 +810,23 @@ static void tcp_splice_state(struct tcp_splice_conn *conn, enum tcp_state state)
  */
 static void tcp_get_sndbuf(struct tcp_tap_conn *conn)
 {
-	int s = conn->sock, v;
+	int s = conn->sock, sndbuf;
 	socklen_t sl;
+	uint64_t v;
 
-	sl = sizeof(v);
+	sl = sizeof(sndbuf);
-	if (getsockopt(s, SOL_SOCKET, SO_SNDBUF, &v, &sl)) {
+	if (getsockopt(s, SOL_SOCKET, SO_SNDBUF, &sndbuf, &sl)) {
 		conn->snd_buf = WINDOW_DEFAULT;
 		return;
 	}
 
+	v = sndbuf;
 	if (v >= SNDBUF_BIG)
 		v /= 2;
 	else if (v > SNDBUF_SMALL)
 		v -= v * (v - SNDBUF_SMALL) / (SNDBUF_BIG - SNDBUF_SMALL) / 2;
 
-	conn->snd_buf = v;
+	conn->snd_buf = MIN(INT_MAX, v);
 }
 
 /**
@@ -1537,17 +1540,17 @@ static size_t tcp_l2_buf_fill_headers(struct ctx *c, struct tcp_tap_conn *conn,
  * @c:		Execution context
  * @conn:	Connection pointer
  * @flags:	TCP header flags we are about to send, if any
- * @info:	tcp_info from kernel, can be NULL if not pre-fetched
+ * @tinfo:	tcp_info from kernel, can be NULL if not pre-fetched
  *
  * Return: 1 if sequence or window were updated, 0 otherwise
  */
 static int tcp_update_seqack_wnd(struct ctx *c, struct tcp_tap_conn *conn,
-				 int flags, struct tcp_info *info)
+				 int flags, struct tcp_info *tinfo)
 {
 	uint32_t prev_ack_to_tap = conn->seq_ack_to_tap;
 	uint32_t prev_wnd_to_tap = conn->wnd_to_tap;
-	socklen_t sl = sizeof(*info);
+	socklen_t sl = sizeof(*tinfo);
-	struct tcp_info info_new;
+	struct tcp_info tinfo_new;
 	int s = conn->sock;
 
 	if (conn->state > ESTABLISHED || (flags & (DUP_ACK | FORCE_ACK)) ||
@@ -1555,13 +1558,13 @@ static int tcp_update_seqack_wnd(struct ctx *c, struct tcp_tap_conn *conn,
 	    conn->snd_buf < SNDBUF_SMALL) {
 		conn->seq_ack_to_tap = conn->seq_from_tap;
 	} else if (conn->seq_ack_to_tap != conn->seq_from_tap) {
-		if (!info) {
+		if (!tinfo) {
-			info = &info_new;
+			tinfo = &tinfo_new;
-			if (getsockopt(s, SOL_TCP, TCP_INFO, info, &sl))
+			if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl))
 				return 0;
 		}
 
-		conn->seq_ack_to_tap = info->tcpi_bytes_acked +
+		conn->seq_ack_to_tap = tinfo->tcpi_bytes_acked +
 				       conn->seq_init_from_tap;
 
 		if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap))
@@ -1574,20 +1577,20 @@ static int tcp_update_seqack_wnd(struct ctx *c, struct tcp_tap_conn *conn,
 		goto out;
 	}
 
-	if (!info) {
+	if (!tinfo) {
 		if (conn->wnd_to_tap > WINDOW_DEFAULT)
 			goto out;
 
-		info = &info_new;
+		tinfo = &tinfo_new;
-		if (getsockopt(s, SOL_TCP, TCP_INFO, info, &sl))
+		if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl))
 			goto out;
 	}
 
 	if (conn->local || tcp_rtt_dst_low(conn)) {
-		conn->wnd_to_tap = info->tcpi_snd_wnd;
+		conn->wnd_to_tap = tinfo->tcpi_snd_wnd;
 	} else {
 		tcp_get_sndbuf(conn);
-		conn->wnd_to_tap = MIN((int)info->tcpi_snd_wnd, conn->snd_buf);
+		conn->wnd_to_tap = MIN((int)tinfo->tcpi_snd_wnd, conn->snd_buf);
 	}
 
 	conn->wnd_to_tap = MIN(conn->wnd_to_tap, MAX_WINDOW);
@@ -1613,8 +1616,8 @@ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags,
 	uint32_t prev_wnd_to_tap = conn->wnd_to_tap;
 	struct tcp4_l2_flags_buf_t *b4 = NULL;
 	struct tcp6_l2_flags_buf_t *b6 = NULL;
-	struct tcp_info info = { 0 };
+	struct tcp_info tinfo = { 0 };
-	socklen_t sl = sizeof(info);
+	socklen_t sl = sizeof(tinfo);
 	size_t optlen = 0, eth_len;
 	int s = conn->sock;
 	struct iovec *iov;
@@ -1626,15 +1629,15 @@ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags,
 	    !flags && conn->wnd_to_tap)
 		return 0;
 
-	if (getsockopt(s, SOL_TCP, TCP_INFO, &info, &sl)) {
+	if (getsockopt(s, SOL_TCP, TCP_INFO, &tinfo, &sl)) {
 		tcp_tap_destroy(c, conn);
 		return -ECONNRESET;
 	}
 
 	if (!conn->local)
-		tcp_rtt_dst_check(conn, &info);
+		tcp_rtt_dst_check(conn, &tinfo);
 
-	if (!tcp_update_seqack_wnd(c, conn, flags, &info) && !flags)
+	if (!tcp_update_seqack_wnd(c, conn, flags, &tinfo) && !flags)
 		return 0;
 
 	if (CONN_V4(conn)) {
@@ -1661,7 +1664,7 @@ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags,
 		*data++ = OPT_MSS_LEN;
 
 		if (c->mtu == -1) {
-			mss = info.tcpi_snd_mss;
+			mss = tinfo.tcpi_snd_mss;
 		} else {
 			mss = c->mtu - sizeof(struct tcphdr);
 			if (CONN_V4(conn))
@@ -1681,11 +1684,11 @@ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags,
 		th->doff += OPT_MSS_LEN / 4;
 
 #ifdef HAS_SND_WND
-		if (!c->tcp.kernel_snd_wnd && info.tcpi_snd_wnd)
+		if (!c->tcp.kernel_snd_wnd && tinfo.tcpi_snd_wnd)
 			c->tcp.kernel_snd_wnd = 1;
 #endif
 
-		conn->ws = MIN(MAX_WS, info.tcpi_snd_wscale);
+		conn->ws = MIN(MAX_WS, tinfo.tcpi_snd_wscale);
 
 		*data++ = OPT_NOP;
 		*data++ = OPT_WS;
@@ -1768,7 +1771,7 @@ static void tcp_rst(struct ctx *c, struct tcp_tap_conn *conn)
 static void tcp_clamp_window(struct tcp_tap_conn *conn, struct tcphdr *th,
 			     int len, unsigned int window, int init)
 {
-	if (init) {
+	if (init && th) {
 		int ws = tcp_opt_get(th, len, OPT_WS, NULL, NULL);
 
 		conn->ws_tap = ws;
@@ -1901,7 +1904,7 @@ static void tcp_conn_from_tap(struct ctx *c, int af, void *addr,
 			sock_pool_p = &init_sock_pool6[i];
 		else
 			sock_pool_p = &init_sock_pool4[i];
-		if ((ref.r.s = s = *sock_pool_p) >= 0) {
+		if ((ref.r.s = s = (*sock_pool_p)) >= 0) {
 			*sock_pool_p = -1;
 			break;
 		}
@@ -2164,7 +2167,7 @@ static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn,
 			      struct timespec *now)
 {
 	int fill_bufs, send_bufs = 0, last_len, iov_rem = 0;
-	int send, len, plen, v4 = CONN_V4(conn);
+	int sendlen, len, plen, v4 = CONN_V4(conn);
 	uint32_t seq_to_tap = conn->seq_to_tap;
 	int s = conn->sock, i, ret = 0;
 	struct msghdr mh_sock = { 0 };
@@ -2226,16 +2229,16 @@ recvmsg:
 	if (!len)
 		goto zero_len;
 
-	send = len - already_sent;
+	sendlen = len - already_sent;
-	if (send <= 0) {
+	if (sendlen <= 0) {
 		tcp_tap_epoll_mask(c, conn, conn->events | EPOLLET);
 		return 0;
 	}
 
 	tcp_tap_epoll_mask(c, conn, conn->events & ~EPOLLET);
 
-	send_bufs = DIV_ROUND_UP(send, conn->mss_guest);
+	send_bufs = DIV_ROUND_UP(sendlen, conn->mss_guest);
-	last_len = send - (send_bufs - 1) * conn->mss_guest;
+	last_len = sendlen - (send_bufs - 1) * conn->mss_guest;
 
 	/* Likely, some new data was acked too. */
 	tcp_update_seqack_wnd(c, conn, 0, NULL);
@@ -2594,7 +2597,7 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
 				conn->mss_guest = MIN(MSS6, conn->mss_guest);
 		}
 
-		/* info.tcpi_bytes_acked already includes one byte for SYN, but
+		/* tinfo.tcpi_bytes_acked already includes one byte for SYN, but
 		 * not for incoming connections.
 		 */
 		conn->seq_init_from_tap = ntohl(th->seq) + 1;
@@ -2787,8 +2790,8 @@ static int tcp_splice_connect(struct ctx *c, struct tcp_splice_conn *conn,
 		.sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) },
 	};
 	const struct sockaddr *sa;
-	int ret, one = 1;
 	socklen_t sl;
+	int one = 1;
 
 	conn->to = sock_conn;
 
@@ -2807,7 +2810,8 @@ static int tcp_splice_connect(struct ctx *c, struct tcp_splice_conn *conn,
 
 	if (connect(conn->to, sa, sl)) {
 		if (errno != EINPROGRESS) {
-			ret = -errno;
+			int ret = -errno;
+
 			close(sock_conn);
 			return ret;
 		}
@@ -3049,10 +3053,8 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 		goto close;
 
 	if (events & EPOLLOUT) {
-		struct epoll_event ev = {
+		ev.events = EPOLLIN | EPOLLRDHUP;
-			.events = EPOLLIN | EPOLLRDHUP,
+		ev.data.u64 = ref.u64;
-			.data.u64 = ref.u64,
-		};
 
 		if (conn->state == SPLICE_CONNECT)
 			tcp_splice_connect_finish(c, conn, ref.r.p.tcp.tcp.v6);
@@ -3111,12 +3113,13 @@ swap:
 
 	while (1) {
 		int retry_write = 0, more = 0;
-		ssize_t read, to_write = 0, written;
+		ssize_t readlen, to_write = 0, written;
 
 retry:
-		read = splice(move_from, NULL, pipes[1], NULL, c->tcp.pipe_size,
+		readlen = splice(move_from, NULL, pipes[1], NULL,
-			      SPLICE_F_MOVE | SPLICE_F_NONBLOCK);
+				 c->tcp.pipe_size,
-		if (read < 0) {
+				 SPLICE_F_MOVE | SPLICE_F_NONBLOCK);
+		if (readlen < 0) {
 			if (errno == EINTR)
 				goto retry;
 
@@ -3124,13 +3127,13 @@ retry:
 				goto close;
 
 			to_write = c->tcp.pipe_size;
-		} else if (!read) {
+		} else if (!readlen) {
 			eof = 1;
 			to_write = c->tcp.pipe_size;
 		} else {
 			never_read = 0;
-			to_write += read;
+			to_write += readlen;
-			if (read >= (long)c->tcp.pipe_size * 90 / 100)
+			if (readlen >= (long)c->tcp.pipe_size * 90 / 100)
 				more = SPLICE_F_MORE;
 
 			if (bitmap_isset(rcvlowat_set, conn - ts))
@@ -3142,12 +3145,12 @@ eintr:
 				 SPLICE_F_MOVE | more | SPLICE_F_NONBLOCK);
 
 		/* Most common case: skip updating counters. */
-		if (read > 0 && read == written) {
+		if (readlen > 0 && readlen == written) {
-			if (read >= (long)c->tcp.pipe_size * 10 / 100)
+			if (readlen >= (long)c->tcp.pipe_size * 10 / 100)
 				continue;
 
 			if (!bitmap_isset(rcvlowat_set, conn - ts) &&
-			    read > (long)c->tcp.pipe_size / 10) {
+			    readlen > (long)c->tcp.pipe_size / 10) {
 				int lowat = c->tcp.pipe_size / 4;
 
 				setsockopt(move_from, SOL_SOCKET, SO_RCVLOWAT,
@@ -3160,7 +3163,7 @@ eintr:
 			break;
 		}
 
-		*seq_read  += read > 0    ? read : 0;
+		*seq_read  += readlen > 0 ? readlen : 0;
 		*seq_write += written > 0 ? written : 0;
 
 		if (written < 0) {

test/build/static_checkers

@@ -11,8 +11,12 @@
 # Copyright (c) 2021 Red Hat GmbH
 # Author: Stefano Brivio <sbrivio@redhat.com>
 
-htools	clang-tidy
+htools	clang-tidy cppcheck
 
 test	Run clang-tidy
 hout	RET make clang-tidy; echo $?
 check	[ __RET__ -eq 0 ]
+
+test	Run cppcheck
+hout	RET make cppcheck; echo $?
+check	[ __RET__ -eq 0 ]

udp.c

@@ -616,9 +616,9 @@ static void udp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 	if (ref.r.p.udp.udp.splice == UDP_TO_NS ||
 	    ref.r.p.udp.udp.splice == UDP_TO_INIT) {
 		for (i = 0; i < n; i++) {
-			struct msghdr *mh = &udp_splice_mmh_send[i].msg_hdr;
+			struct msghdr *mh_s = &udp_splice_mmh_send[i].msg_hdr;
 
-			mh->msg_iov->iov_len = udp_splice_mmh_recv[i].msg_len;
+			mh_s->msg_iov->iov_len = udp_splice_mmh_recv[i].msg_len;
 		}
 
 		sendmmsg(s, udp_splice_mmh_send, n, MSG_NOSIGNAL);
@@ -626,9 +626,9 @@ static void udp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 	}
 
 	for (i = 0; i < n; i++) {
-		struct msghdr *mh = &udp_splice_mmh_sendto[i].msg_hdr;
+		struct msghdr *mh_s = &udp_splice_mmh_sendto[i].msg_hdr;
 
-		mh->msg_iov->iov_len = udp_splice_mmh_recv[i].msg_len;
+		mh_s->msg_iov->iov_len = udp_splice_mmh_recv[i].msg_len;
 	}
 
 	if (v6) {
@@ -710,8 +710,6 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
 				else
 					b->ip6h.saddr = c->addr6_ll;
 
-				b->ip6h.saddr = c->gw6;
-
 				udp_tap_map[V6][src].ts_local = now->tv_sec;
 
 				if (IN6_IS_ADDR_LOOPBACK(&b->s_in6.sin6_addr))
@@ -1000,11 +998,11 @@ int udp_tap_handler(struct ctx *c, int af, void *addr,
 	}
 
 	for (i = 0; i < count; i++) {
-		struct udphdr *uh;
+		struct udphdr *uh_send;
 
-		uh = (struct udphdr *)(msg[i].pkt_buf_offset + pkt_buf);
+		uh_send = (struct udphdr *)(msg[i].pkt_buf_offset + pkt_buf);
-		m[i].iov_base = (char *)(uh + 1);
+		m[i].iov_base = (char *)(uh_send + 1);
-		m[i].iov_len = msg[i].l4_len - sizeof(*uh);
+		m[i].iov_len = msg[i].l4_len - sizeof(*uh_send);
 
 		mm[i].msg_hdr.msg_name = sa;
 		mm[i].msg_hdr.msg_namelen = sl;

util.c

@@ -51,7 +51,7 @@ void name(const char *format, ...) {					\
 									\
 	if (setlogmask(0) & LOG_MASK(LOG_DEBUG)) {			\
 		clock_gettime(CLOCK_REALTIME, &tp);			\
-		fprintf(stderr, "%lu.%04lu: ",				\
+		fprintf(stderr, "%li.%04li: ",				\
 			tp.tv_sec - log_debug_start,			\
 			tp.tv_nsec / (100 * 1000));			\
 	} else {							\
@@ -142,7 +142,7 @@ void passt_vsyslog(int pri, const char *format, va_list ap)
 	if (format[strlen(format)] != '\n')
 		n += snprintf(buf + n, BUFSIZ - n, "\n");
 
-	if (log_opt | LOG_PERROR)
+	if (log_opt & LOG_PERROR)
 		fprintf(stderr, "%s", buf + sizeof("<0>"));
 
 	send(log_sock, buf, n, 0);