/*
- * Copyright (c) 2009 Nicira Networks.
+ * Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <config.h>
#include "packets.h"
+#include <assert.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
+#include "byte-order.h"
+#include "csum.h"
+#include "flow.h"
+#include "hmap.h"
+#include "dynamic-string.h"
#include "ofpbuf.h"
+const struct in6_addr in6addr_exact = IN6ADDR_EXACT_INIT;
+
+/* Parses 's' as a 16-digit hexadecimal number representing a datapath ID. On
+ * success stores the dpid into '*dpidp' and returns true, on failure stores 0
+ * into '*dpidp' and returns false.
+ *
+ * Rejects an all-zeros dpid as invalid. */
bool
dpid_from_string(const char *s, uint64_t *dpidp)
{
- *dpidp = (strlen(s) == 12 && strspn(s, "0123456789abcdefABCDEF") == 12
- ? strtoll(s, NULL, 16)
+ *dpidp = (strlen(s) == 16 && strspn(s, "0123456789abcdefABCDEF") == 16
+ ? strtoull(s, NULL, 16)
: 0);
return *dpidp != 0;
}
+/* Returns true if 'ea' is a reserved address, that a bridge must never
+ * forward, false otherwise.
+ *
+ * If you change this function's behavior, please update corresponding
+ * documentation in vswitch.xml at the same time. */
+bool
+eth_addr_is_reserved(const uint8_t ea[ETH_ADDR_LEN])
+{
+ struct eth_addr_node {
+ struct hmap_node hmap_node;
+ uint64_t ea64;
+ };
+
+ static struct eth_addr_node nodes[] = {
+ /* STP, IEEE pause frames, and other reserved protocols. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000000ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000001ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000002ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000003ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000004ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000005ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000006ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000007ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000008ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c2000009ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c200000aULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c200000bULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c200000cULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c200000dULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c200000eULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x0108c200000fULL },
+
+ /* Extreme protocols. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x00e02b000000ULL }, /* EDP. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x00e02b000004ULL }, /* EAPS. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x00e02b000006ULL }, /* EAPS. */
+
+ /* Cisco protocols. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000c000000ULL }, /* ISL. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccccULL }, /* PAgP, UDLD, CDP,
+ * DTP, VTP. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000ccccccdULL }, /* PVST+. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000ccdcdcdULL }, /* STP Uplink Fast,
+ * FlexLink. */
+
+ /* Cisco CFM. */
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc0ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc1ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc2ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc3ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc4ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc5ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc6ULL },
+ { HMAP_NODE_NULL_INITIALIZER, 0x01000cccccc7ULL },
+ };
+
+ static struct hmap addrs = HMAP_INITIALIZER(&addrs);
+ struct eth_addr_node *node;
+ uint64_t ea64;
+
+ if (hmap_is_empty(&addrs)) {
+ for (node = nodes; node < &nodes[ARRAY_SIZE(nodes)]; node++) {
+ hmap_insert(&addrs, &node->hmap_node,
+ hash_2words(node->ea64, node->ea64 >> 32));
+ }
+ }
+
+ ea64 = eth_addr_to_uint64(ea);
+ HMAP_FOR_EACH_IN_BUCKET (node, hmap_node, hash_2words(ea64, ea64 >> 32),
+ &addrs) {
+ if (node->ea64 == ea64) {
+ return true;
+ }
+ }
+ return false;
+}
+
bool
eth_addr_from_string(const char *s, uint8_t ea[ETH_ADDR_LEN])
{
}
}
-/* Fills 'b' with an 802.2 SNAP packet with Ethernet source address 'eth_src',
- * the Nicira OUI as SNAP organization and 'snap_type' as SNAP type. The text
- * string in 'tag' is enclosed as the packet payload.
- *
+/* Fills 'b' with a Reverse ARP packet with Ethernet source address 'eth_src'.
* This function is used by Open vSwitch to compose packets in cases where
- * context is important but content doesn't (or shouldn't) matter. For this
- * purpose, 'snap_type' should be a random number and 'tag' should be an
- * English phrase that explains the purpose of the packet. (The English phrase
- * gives hapless admins running Wireshark the opportunity to figure out what's
- * going on.) */
+ * context is important but content doesn't (or shouldn't) matter.
+ *
+ * The returned packet has enough headroom to insert an 802.1Q VLAN header if
+ * desired. */
void
-compose_benign_packet(struct ofpbuf *b, const char *tag, uint16_t snap_type,
- const uint8_t eth_src[ETH_ADDR_LEN])
+compose_rarp(struct ofpbuf *b, const uint8_t eth_src[ETH_ADDR_LEN])
{
struct eth_header *eth;
- struct llc_snap_header *llc_snap;
+ struct arp_eth_header *arp;
- /* Compose basic packet structure. (We need the payload size to stick into
- * the 802.2 header.) */
ofpbuf_clear(b);
- eth = ofpbuf_put_zeros(b, ETH_HEADER_LEN);
- llc_snap = ofpbuf_put_zeros(b, LLC_SNAP_HEADER_LEN);
- ofpbuf_put(b, tag, strlen(tag) + 1); /* Includes null byte. */
- ofpbuf_put(b, eth_src, ETH_ADDR_LEN);
-
- /* Compose 802.2 header. */
+ ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN
+ + ARP_ETH_HEADER_LEN);
+ ofpbuf_reserve(b, VLAN_HEADER_LEN);
+ eth = ofpbuf_put_uninit(b, sizeof *eth);
memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
- eth->eth_type = htons(b->size - ETH_HEADER_LEN);
-
- /* Compose LLC, SNAP headers. */
- llc_snap->llc.llc_dsap = LLC_DSAP_SNAP;
- llc_snap->llc.llc_ssap = LLC_SSAP_SNAP;
- llc_snap->llc.llc_cntl = LLC_CNTL_SNAP;
- memcpy(llc_snap->snap.snap_org, "\x00\x23\x20", 3);
- llc_snap->snap.snap_type = htons(snap_type);
+ eth->eth_type = htons(ETH_TYPE_RARP);
+
+ arp = ofpbuf_put_uninit(b, sizeof *arp);
+ arp->ar_hrd = htons(ARP_HRD_ETHERNET);
+ arp->ar_pro = htons(ARP_PRO_IP);
+ arp->ar_hln = sizeof arp->ar_sha;
+ arp->ar_pln = sizeof arp->ar_spa;
+ arp->ar_op = htons(ARP_OP_RARP);
+ memcpy(arp->ar_sha, eth_src, ETH_ADDR_LEN);
+ arp->ar_spa = htonl(0);
+ memcpy(arp->ar_tha, eth_src, ETH_ADDR_LEN);
+ arp->ar_tpa = htonl(0);
+}
+
+/* Insert VLAN header according to given TCI. Packet passed must be Ethernet
+ * packet. Ignores the CFI bit of 'tci' using 0 instead.
+ *
+ * Also sets 'packet->l2' to point to the new Ethernet header. */
+void
+eth_push_vlan(struct ofpbuf *packet, ovs_be16 tci)
+{
+ struct eth_header *eh = packet->data;
+ struct vlan_eth_header *veh;
+
+ /* Insert new 802.1Q header. */
+ struct vlan_eth_header tmp;
+ memcpy(tmp.veth_dst, eh->eth_dst, ETH_ADDR_LEN);
+ memcpy(tmp.veth_src, eh->eth_src, ETH_ADDR_LEN);
+ tmp.veth_type = htons(ETH_TYPE_VLAN);
+ tmp.veth_tci = tci & htons(~VLAN_CFI);
+ tmp.veth_next_type = eh->eth_type;
+
+ veh = ofpbuf_push_uninit(packet, VLAN_HEADER_LEN);
+ memcpy(veh, &tmp, sizeof tmp);
+
+ packet->l2 = packet->data;
+}
+
+/* Removes outermost VLAN header (if any is present) from 'packet'.
+ *
+ * 'packet->l2' must initially point to 'packet''s Ethernet header. */
+void
+eth_pop_vlan(struct ofpbuf *packet)
+{
+ struct vlan_eth_header *veh = packet->l2;
+ if (packet->size >= sizeof *veh
+ && veh->veth_type == htons(ETH_TYPE_VLAN)) {
+ struct eth_header tmp;
+
+ memcpy(tmp.eth_dst, veh->veth_dst, ETH_ADDR_LEN);
+ memcpy(tmp.eth_src, veh->veth_src, ETH_ADDR_LEN);
+ tmp.eth_type = veh->veth_next_type;
+
+ ofpbuf_pull(packet, VLAN_HEADER_LEN);
+ packet->l2 = (char*)packet->l2 + VLAN_HEADER_LEN;
+ memcpy(packet->data, &tmp, sizeof tmp);
+ }
+}
+
+/* Converts hex digits in 'hex' to an Ethernet packet in '*packetp'. The
+ * caller must free '*packetp'. On success, returns NULL. On failure, returns
+ * an error message and stores NULL in '*packetp'. */
+const char *
+eth_from_hex(const char *hex, struct ofpbuf **packetp)
+{
+ struct ofpbuf *packet;
+
+ packet = *packetp = ofpbuf_new(strlen(hex) / 2);
+
+ if (ofpbuf_put_hex(packet, hex, NULL)[0] != '\0') {
+ ofpbuf_delete(packet);
+ *packetp = NULL;
+ return "Trailing garbage in packet data";
+ }
+
+ if (packet->size < ETH_HEADER_LEN) {
+ ofpbuf_delete(packet);
+ *packetp = NULL;
+ return "Packet data too short for Ethernet";
+ }
+
+ return NULL;
+}
+
+void
+eth_format_masked(const uint8_t eth[ETH_ADDR_LEN],
+ const uint8_t mask[ETH_ADDR_LEN], struct ds *s)
+{
+ ds_put_format(s, ETH_ADDR_FMT, ETH_ADDR_ARGS(eth));
+ if (mask && !eth_mask_is_exact(mask)) {
+ ds_put_format(s, "/"ETH_ADDR_FMT, ETH_ADDR_ARGS(mask));
+ }
+}
+
+void
+eth_addr_bitand(const uint8_t src[ETH_ADDR_LEN],
+ const uint8_t mask[ETH_ADDR_LEN],
+ uint8_t dst[ETH_ADDR_LEN])
+{
+ int i;
+
+ for (i = 0; i < ETH_ADDR_LEN; i++) {
+ dst[i] = src[i] & mask[i];
+ }
+}
+
+/* Given the IP netmask 'netmask', returns the number of bits of the IP address
+ * that it specifies, that is, the number of 1-bits in 'netmask'.
+ *
+ * If 'netmask' is not a CIDR netmask (see ip_is_cidr()), the return value will
+ * still be in the valid range but isn't otherwise meaningful. */
+int
+ip_count_cidr_bits(ovs_be32 netmask)
+{
+ return 32 - ctz(ntohl(netmask));
+}
+
+void
+ip_format_masked(ovs_be32 ip, ovs_be32 mask, struct ds *s)
+{
+ ds_put_format(s, IP_FMT, IP_ARGS(&ip));
+ if (mask != htonl(UINT32_MAX)) {
+ if (ip_is_cidr(mask)) {
+ ds_put_format(s, "/%d", ip_count_cidr_bits(mask));
+ } else {
+ ds_put_format(s, "/"IP_FMT, IP_ARGS(&mask));
+ }
+ }
+}
+
+
+/* Stores the string representation of the IPv6 address 'addr' into the
+ * character array 'addr_str', which must be at least INET6_ADDRSTRLEN
+ * bytes long. */
+void
+format_ipv6_addr(char *addr_str, const struct in6_addr *addr)
+{
+ inet_ntop(AF_INET6, addr, addr_str, INET6_ADDRSTRLEN);
+}
+
+void
+print_ipv6_addr(struct ds *string, const struct in6_addr *addr)
+{
+ char *dst;
+
+ ds_reserve(string, string->length + INET6_ADDRSTRLEN);
+
+ dst = string->string + string->length;
+ format_ipv6_addr(dst, addr);
+ string->length += strlen(dst);
+}
+
+void
+print_ipv6_masked(struct ds *s, const struct in6_addr *addr,
+ const struct in6_addr *mask)
+{
+ print_ipv6_addr(s, addr);
+ if (mask && !ipv6_mask_is_exact(mask)) {
+ if (ipv6_is_cidr(mask)) {
+ int cidr_bits = ipv6_count_cidr_bits(mask);
+ ds_put_format(s, "/%d", cidr_bits);
+ } else {
+ ds_put_char(s, '/');
+ print_ipv6_addr(s, mask);
+ }
+ }
+}
+
+struct in6_addr ipv6_addr_bitand(const struct in6_addr *a,
+ const struct in6_addr *b)
+{
+ int i;
+ struct in6_addr dst;
+
+#ifdef s6_addr32
+ for (i=0; i<4; i++) {
+ dst.s6_addr32[i] = a->s6_addr32[i] & b->s6_addr32[i];
+ }
+#else
+ for (i=0; i<16; i++) {
+ dst.s6_addr[i] = a->s6_addr[i] & b->s6_addr[i];
+ }
+#endif
+
+ return dst;
+}
+
+/* Returns an in6_addr consisting of 'mask' high-order 1-bits and 128-N
+ * low-order 0-bits. */
+struct in6_addr
+ipv6_create_mask(int mask)
+{
+ struct in6_addr netmask;
+ uint8_t *netmaskp = &netmask.s6_addr[0];
+
+ memset(&netmask, 0, sizeof netmask);
+ while (mask > 8) {
+ *netmaskp = 0xff;
+ netmaskp++;
+ mask -= 8;
+ }
+
+ if (mask) {
+ *netmaskp = 0xff << (8 - mask);
+ }
+
+ return netmask;
+}
+
+/* Given the IPv6 netmask 'netmask', returns the number of bits of the IPv6
+ * address that it specifies, that is, the number of 1-bits in 'netmask'.
+ * 'netmask' must be a CIDR netmask (see ipv6_is_cidr()).
+ *
+ * If 'netmask' is not a CIDR netmask (see ipv6_is_cidr()), the return value
+ * will still be in the valid range but isn't otherwise meaningful. */
+int
+ipv6_count_cidr_bits(const struct in6_addr *netmask)
+{
+ int i;
+ int count = 0;
+ const uint8_t *netmaskp = &netmask->s6_addr[0];
+
+ for (i=0; i<16; i++) {
+ if (netmaskp[i] == 0xff) {
+ count += 8;
+ } else {
+ uint8_t nm;
+
+ for(nm = netmaskp[i]; nm; nm <<= 1) {
+ count++;
+ }
+ break;
+ }
+
+ }
+
+ return count;
+}
+
+/* Returns true if 'netmask' is a CIDR netmask, that is, if it consists of N
+ * high-order 1-bits and 128-N low-order 0-bits. */
+bool
+ipv6_is_cidr(const struct in6_addr *netmask)
+{
+ const uint8_t *netmaskp = &netmask->s6_addr[0];
+ int i;
+
+ for (i=0; i<16; i++) {
+ if (netmaskp[i] != 0xff) {
+ uint8_t x = ~netmaskp[i];
+ if (x & (x + 1)) {
+ return false;
+ }
+ while (++i < 16) {
+ if (netmaskp[i]) {
+ return false;
+ }
+ }
+ }
+ }
+
+ return true;
+}
+
+/* Populates 'b' with an Ethernet II packet headed with the given 'eth_dst',
+ * 'eth_src' and 'eth_type' parameters. A payload of 'size' bytes is allocated
+ * in 'b' and returned. This payload may be populated with appropriate
+ * information by the caller. Sets 'b''s 'l2' and 'l3' pointers to the
+ * Ethernet header and payload respectively.
+ *
+ * The returned packet has enough headroom to insert an 802.1Q VLAN header if
+ * desired. */
+void *
+eth_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN],
+ const uint8_t eth_src[ETH_ADDR_LEN], uint16_t eth_type,
+ size_t size)
+{
+ void *data;
+ struct eth_header *eth;
+
+ ofpbuf_clear(b);
+
+ ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN + size);
+ ofpbuf_reserve(b, VLAN_HEADER_LEN);
+ eth = ofpbuf_put_uninit(b, ETH_HEADER_LEN);
+ data = ofpbuf_put_uninit(b, size);
+
+ memcpy(eth->eth_dst, eth_dst, ETH_ADDR_LEN);
+ memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
+ eth->eth_type = htons(eth_type);
+
+ b->l2 = eth;
+ b->l3 = data;
+
+ return data;
+}
+
+static void
+packet_set_ipv4_addr(struct ofpbuf *packet, ovs_be32 *addr, ovs_be32 new_addr)
+{
+ struct ip_header *nh = packet->l3;
+
+ if (nh->ip_proto == IPPROTO_TCP && packet->l7) {
+ struct tcp_header *th = packet->l4;
+
+ th->tcp_csum = recalc_csum32(th->tcp_csum, *addr, new_addr);
+ } else if (nh->ip_proto == IPPROTO_UDP && packet->l7) {
+ struct udp_header *uh = packet->l4;
+
+ if (uh->udp_csum) {
+ uh->udp_csum = recalc_csum32(uh->udp_csum, *addr, new_addr);
+ if (!uh->udp_csum) {
+ uh->udp_csum = htons(0xffff);
+ }
+ }
+ }
+ nh->ip_csum = recalc_csum32(nh->ip_csum, *addr, new_addr);
+ *addr = new_addr;
+}
+
+/* Modifies the IPv4 header fields of 'packet' to be consistent with 'src',
+ * 'dst', 'tos', and 'ttl'. Updates 'packet''s L4 checksums as appropriate.
+ * 'packet' must contain a valid IPv4 packet with correctly populated l[347]
+ * markers. */
+void
+packet_set_ipv4(struct ofpbuf *packet, ovs_be32 src, ovs_be32 dst,
+ uint8_t tos, uint8_t ttl)
+{
+ struct ip_header *nh = packet->l3;
+
+ if (nh->ip_src != src) {
+ packet_set_ipv4_addr(packet, &nh->ip_src, src);
+ }
+
+ if (nh->ip_dst != dst) {
+ packet_set_ipv4_addr(packet, &nh->ip_dst, dst);
+ }
+
+ if (nh->ip_tos != tos) {
+ uint8_t *field = &nh->ip_tos;
+
+ nh->ip_csum = recalc_csum16(nh->ip_csum, htons((uint16_t) *field),
+ htons((uint16_t) tos));
+ *field = tos;
+ }
+
+ if (nh->ip_ttl != ttl) {
+ uint8_t *field = &nh->ip_ttl;
+
+ nh->ip_csum = recalc_csum16(nh->ip_csum, htons(*field << 8),
+ htons(ttl << 8));
+ *field = ttl;
+ }
+}
+
+static void
+packet_set_port(ovs_be16 *port, ovs_be16 new_port, ovs_be16 *csum)
+{
+ if (*port != new_port) {
+ *csum = recalc_csum16(*csum, *port, new_port);
+ *port = new_port;
+ }
+}
+
+/* Sets the TCP source and destination port ('src' and 'dst' respectively) of
+ * the TCP header contained in 'packet'. 'packet' must be a valid TCP packet
+ * with its l4 marker properly populated. */
+void
+packet_set_tcp_port(struct ofpbuf *packet, ovs_be16 src, ovs_be16 dst)
+{
+ struct tcp_header *th = packet->l4;
+
+ packet_set_port(&th->tcp_src, src, &th->tcp_csum);
+ packet_set_port(&th->tcp_dst, dst, &th->tcp_csum);
+}
+
+/* Sets the UDP source and destination port ('src' and 'dst' respectively) of
+ * the UDP header contained in 'packet'. 'packet' must be a valid UDP packet
+ * with its l4 marker properly populated. */
+void
+packet_set_udp_port(struct ofpbuf *packet, ovs_be16 src, ovs_be16 dst)
+{
+ struct udp_header *uh = packet->l4;
+
+ if (uh->udp_csum) {
+ packet_set_port(&uh->udp_src, src, &uh->udp_csum);
+ packet_set_port(&uh->udp_dst, dst, &uh->udp_csum);
+
+ if (!uh->udp_csum) {
+ uh->udp_csum = htons(0xffff);
+ }
+ } else {
+ uh->udp_src = src;
+ uh->udp_dst = dst;
+ }
+}
+
+/* If 'packet' is a TCP packet, returns the TCP flags. Otherwise, returns 0.
+ *
+ * 'flow' must be the flow corresponding to 'packet' and 'packet''s header
+ * pointers must be properly initialized (e.g. with flow_extract()). */
+uint8_t
+packet_get_tcp_flags(const struct ofpbuf *packet, const struct flow *flow)
+{
+ if ((flow->dl_type == htons(ETH_TYPE_IP) ||
+ flow->dl_type == htons(ETH_TYPE_IPV6)) &&
+ flow->nw_proto == IPPROTO_TCP && packet->l7) {
+ const struct tcp_header *tcp = packet->l4;
+ return TCP_FLAGS(tcp->tcp_ctl);
+ } else {
+ return 0;
+ }
+}
+
+/* Appends a string representation of the TCP flags value 'tcp_flags'
+ * (e.g. obtained via packet_get_tcp_flags() or TCP_FLAGS) to 's', in the
+ * format used by tcpdump. */
+void
+packet_format_tcp_flags(struct ds *s, uint8_t tcp_flags)
+{
+ if (!tcp_flags) {
+ ds_put_cstr(s, "none");
+ return;
+ }
+
+ if (tcp_flags & TCP_SYN) {
+ ds_put_char(s, 'S');
+ }
+ if (tcp_flags & TCP_FIN) {
+ ds_put_char(s, 'F');
+ }
+ if (tcp_flags & TCP_PSH) {
+ ds_put_char(s, 'P');
+ }
+ if (tcp_flags & TCP_RST) {
+ ds_put_char(s, 'R');
+ }
+ if (tcp_flags & TCP_URG) {
+ ds_put_char(s, 'U');
+ }
+ if (tcp_flags & TCP_ACK) {
+ ds_put_char(s, '.');
+ }
+ if (tcp_flags & 0x40) {
+ ds_put_cstr(s, "[40]");
+ }
+ if (tcp_flags & 0x80) {
+ ds_put_cstr(s, "[80]");
+ }
}