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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /tools/testing/selftests/net/gro.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/net/gro.c')
-rw-r--r--tools/testing/selftests/net/gro.c1106
1 files changed, 1106 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/gro.c b/tools/testing/selftests/net/gro.c
new file mode 100644
index 000000000..30024d0ed
--- /dev/null
+++ b/tools/testing/selftests/net/gro.c
@@ -0,0 +1,1106 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This testsuite provides conformance testing for GRO coalescing.
+ *
+ * Test cases:
+ * 1.data
+ * Data packets of the same size and same header setup with correct
+ * sequence numbers coalesce. The one exception being the last data
+ * packet coalesced: it can be smaller than the rest and coalesced
+ * as long as it is in the same flow.
+ * 2.ack
+ * Pure ACK does not coalesce.
+ * 3.flags
+ * Specific test cases: no packets with PSH, SYN, URG, RST set will
+ * be coalesced.
+ * 4.tcp
+ * Packets with incorrect checksum, non-consecutive seqno and
+ * different TCP header options shouldn't coalesce. Nit: given that
+ * some extension headers have paddings, such as timestamp, headers
+ * that are padding differently would not be coalesced.
+ * 5.ip:
+ * Packets with different (ECN, TTL, TOS) header, ip options or
+ * ip fragments (ipv6) shouldn't coalesce.
+ * 6.large:
+ * Packets larger than GRO_MAX_SIZE packets shouldn't coalesce.
+ *
+ * MSS is defined as 4096 - header because if it is too small
+ * (i.e. 1500 MTU - header), it will result in many packets,
+ * increasing the "large" test case's flakiness. This is because
+ * due to time sensitivity in the coalescing window, the receiver
+ * may not coalesce all of the packets.
+ *
+ * Note the timing issue applies to all of the test cases, so some
+ * flakiness is to be expected.
+ *
+ */
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <getopt.h>
+#include <linux/filter.h>
+#include <linux/if_packet.h>
+#include <linux/ipv6.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/tcp.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+
+#define DPORT 8000
+#define SPORT 1500
+#define PAYLOAD_LEN 100
+#define NUM_PACKETS 4
+#define START_SEQ 100
+#define START_ACK 100
+#define ETH_P_NONE 0
+#define TOTAL_HDR_LEN (ETH_HLEN + sizeof(struct ipv6hdr) + sizeof(struct tcphdr))
+#define MSS (4096 - sizeof(struct tcphdr) - sizeof(struct ipv6hdr))
+#define MAX_PAYLOAD (IP_MAXPACKET - sizeof(struct tcphdr) - sizeof(struct ipv6hdr))
+#define NUM_LARGE_PKT (MAX_PAYLOAD / MSS)
+#define MAX_HDR_LEN (ETH_HLEN + sizeof(struct ipv6hdr) + sizeof(struct tcphdr))
+
+static const char *addr6_src = "fdaa::2";
+static const char *addr6_dst = "fdaa::1";
+static const char *addr4_src = "192.168.1.200";
+static const char *addr4_dst = "192.168.1.100";
+static int proto = -1;
+static uint8_t src_mac[ETH_ALEN], dst_mac[ETH_ALEN];
+static char *testname = "data";
+static char *ifname = "eth0";
+static char *smac = "aa:00:00:00:00:02";
+static char *dmac = "aa:00:00:00:00:01";
+static bool verbose;
+static bool tx_socket = true;
+static int tcp_offset = -1;
+static int total_hdr_len = -1;
+static int ethhdr_proto = -1;
+
+static void vlog(const char *fmt, ...)
+{
+ va_list args;
+
+ if (verbose) {
+ va_start(args, fmt);
+ vfprintf(stderr, fmt, args);
+ va_end(args);
+ }
+}
+
+static void setup_sock_filter(int fd)
+{
+ const int dport_off = tcp_offset + offsetof(struct tcphdr, dest);
+ const int ethproto_off = offsetof(struct ethhdr, h_proto);
+ int optlen = 0;
+ int ipproto_off;
+ int next_off;
+
+ if (proto == PF_INET)
+ next_off = offsetof(struct iphdr, protocol);
+ else
+ next_off = offsetof(struct ipv6hdr, nexthdr);
+ ipproto_off = ETH_HLEN + next_off;
+
+ if (strcmp(testname, "ip") == 0) {
+ if (proto == PF_INET)
+ optlen = sizeof(struct ip_timestamp);
+ else
+ optlen = sizeof(struct ip6_frag);
+ }
+
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, ethproto_off),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ntohs(ethhdr_proto), 0, 7),
+ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, ipproto_off),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_TCP, 0, 5),
+ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, dport_off),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DPORT, 2, 0),
+ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, dport_off + optlen),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DPORT, 0, 1),
+ BPF_STMT(BPF_RET + BPF_K, 0xFFFFFFFF),
+ BPF_STMT(BPF_RET + BPF_K, 0),
+ };
+
+ struct sock_fprog bpf = {
+ .len = ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+
+ if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf)) < 0)
+ error(1, errno, "error setting filter");
+}
+
+static uint32_t checksum_nofold(void *data, size_t len, uint32_t sum)
+{
+ uint16_t *words = data;
+ int i;
+
+ for (i = 0; i < len / 2; i++)
+ sum += words[i];
+ if (len & 1)
+ sum += ((char *)data)[len - 1];
+ return sum;
+}
+
+static uint16_t checksum_fold(void *data, size_t len, uint32_t sum)
+{
+ sum = checksum_nofold(data, len, sum);
+ while (sum > 0xFFFF)
+ sum = (sum & 0xFFFF) + (sum >> 16);
+ return ~sum;
+}
+
+static uint16_t tcp_checksum(void *buf, int payload_len)
+{
+ struct pseudo_header6 {
+ struct in6_addr saddr;
+ struct in6_addr daddr;
+ uint16_t protocol;
+ uint16_t payload_len;
+ } ph6;
+ struct pseudo_header4 {
+ struct in_addr saddr;
+ struct in_addr daddr;
+ uint16_t protocol;
+ uint16_t payload_len;
+ } ph4;
+ uint32_t sum = 0;
+
+ if (proto == PF_INET6) {
+ if (inet_pton(AF_INET6, addr6_src, &ph6.saddr) != 1)
+ error(1, errno, "inet_pton6 source ip pseudo");
+ if (inet_pton(AF_INET6, addr6_dst, &ph6.daddr) != 1)
+ error(1, errno, "inet_pton6 dest ip pseudo");
+ ph6.protocol = htons(IPPROTO_TCP);
+ ph6.payload_len = htons(sizeof(struct tcphdr) + payload_len);
+
+ sum = checksum_nofold(&ph6, sizeof(ph6), 0);
+ } else if (proto == PF_INET) {
+ if (inet_pton(AF_INET, addr4_src, &ph4.saddr) != 1)
+ error(1, errno, "inet_pton source ip pseudo");
+ if (inet_pton(AF_INET, addr4_dst, &ph4.daddr) != 1)
+ error(1, errno, "inet_pton dest ip pseudo");
+ ph4.protocol = htons(IPPROTO_TCP);
+ ph4.payload_len = htons(sizeof(struct tcphdr) + payload_len);
+
+ sum = checksum_nofold(&ph4, sizeof(ph4), 0);
+ }
+
+ return checksum_fold(buf, sizeof(struct tcphdr) + payload_len, sum);
+}
+
+static void read_MAC(uint8_t *mac_addr, char *mac)
+{
+ if (sscanf(mac, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
+ &mac_addr[0], &mac_addr[1], &mac_addr[2],
+ &mac_addr[3], &mac_addr[4], &mac_addr[5]) != 6)
+ error(1, 0, "sscanf");
+}
+
+static void fill_datalinklayer(void *buf)
+{
+ struct ethhdr *eth = buf;
+
+ memcpy(eth->h_dest, dst_mac, ETH_ALEN);
+ memcpy(eth->h_source, src_mac, ETH_ALEN);
+ eth->h_proto = ethhdr_proto;
+}
+
+static void fill_networklayer(void *buf, int payload_len)
+{
+ struct ipv6hdr *ip6h = buf;
+ struct iphdr *iph = buf;
+
+ if (proto == PF_INET6) {
+ memset(ip6h, 0, sizeof(*ip6h));
+
+ ip6h->version = 6;
+ ip6h->payload_len = htons(sizeof(struct tcphdr) + payload_len);
+ ip6h->nexthdr = IPPROTO_TCP;
+ ip6h->hop_limit = 8;
+ if (inet_pton(AF_INET6, addr6_src, &ip6h->saddr) != 1)
+ error(1, errno, "inet_pton source ip6");
+ if (inet_pton(AF_INET6, addr6_dst, &ip6h->daddr) != 1)
+ error(1, errno, "inet_pton dest ip6");
+ } else if (proto == PF_INET) {
+ memset(iph, 0, sizeof(*iph));
+
+ iph->version = 4;
+ iph->ihl = 5;
+ iph->ttl = 8;
+ iph->protocol = IPPROTO_TCP;
+ iph->tot_len = htons(sizeof(struct tcphdr) +
+ payload_len + sizeof(struct iphdr));
+ iph->frag_off = htons(0x4000); /* DF = 1, MF = 0 */
+ if (inet_pton(AF_INET, addr4_src, &iph->saddr) != 1)
+ error(1, errno, "inet_pton source ip");
+ if (inet_pton(AF_INET, addr4_dst, &iph->daddr) != 1)
+ error(1, errno, "inet_pton dest ip");
+ iph->check = checksum_fold(buf, sizeof(struct iphdr), 0);
+ }
+}
+
+static void fill_transportlayer(void *buf, int seq_offset, int ack_offset,
+ int payload_len, int fin)
+{
+ struct tcphdr *tcph = buf;
+
+ memset(tcph, 0, sizeof(*tcph));
+
+ tcph->source = htons(SPORT);
+ tcph->dest = htons(DPORT);
+ tcph->seq = ntohl(START_SEQ + seq_offset);
+ tcph->ack_seq = ntohl(START_ACK + ack_offset);
+ tcph->ack = 1;
+ tcph->fin = fin;
+ tcph->doff = 5;
+ tcph->window = htons(TCP_MAXWIN);
+ tcph->urg_ptr = 0;
+ tcph->check = tcp_checksum(tcph, payload_len);
+}
+
+static void write_packet(int fd, char *buf, int len, struct sockaddr_ll *daddr)
+{
+ int ret = -1;
+
+ ret = sendto(fd, buf, len, 0, (struct sockaddr *)daddr, sizeof(*daddr));
+ if (ret == -1)
+ error(1, errno, "sendto failure");
+ if (ret != len)
+ error(1, errno, "sendto wrong length");
+}
+
+static void create_packet(void *buf, int seq_offset, int ack_offset,
+ int payload_len, int fin)
+{
+ memset(buf, 0, total_hdr_len);
+ memset(buf + total_hdr_len, 'a', payload_len);
+ fill_transportlayer(buf + tcp_offset, seq_offset, ack_offset,
+ payload_len, fin);
+ fill_networklayer(buf + ETH_HLEN, payload_len);
+ fill_datalinklayer(buf);
+}
+
+/* send one extra flag, not first and not last pkt */
+static void send_flags(int fd, struct sockaddr_ll *daddr, int psh, int syn,
+ int rst, int urg)
+{
+ static char flag_buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ int payload_len, pkt_size, flag, i;
+ struct tcphdr *tcph;
+
+ payload_len = PAYLOAD_LEN * psh;
+ pkt_size = total_hdr_len + payload_len;
+ flag = NUM_PACKETS / 2;
+
+ create_packet(flag_buf, flag * payload_len, 0, payload_len, 0);
+
+ tcph = (struct tcphdr *)(flag_buf + tcp_offset);
+ tcph->psh = psh;
+ tcph->syn = syn;
+ tcph->rst = rst;
+ tcph->urg = urg;
+ tcph->check = 0;
+ tcph->check = tcp_checksum(tcph, payload_len);
+
+ for (i = 0; i < NUM_PACKETS + 1; i++) {
+ if (i == flag) {
+ write_packet(fd, flag_buf, pkt_size, daddr);
+ continue;
+ }
+ create_packet(buf, i * PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, total_hdr_len + PAYLOAD_LEN, daddr);
+ }
+}
+
+/* Test for data of same length, smaller than previous
+ * and of different lengths
+ */
+static void send_data_pkts(int fd, struct sockaddr_ll *daddr,
+ int payload_len1, int payload_len2)
+{
+ static char buf[ETH_HLEN + IP_MAXPACKET];
+
+ create_packet(buf, 0, 0, payload_len1, 0);
+ write_packet(fd, buf, total_hdr_len + payload_len1, daddr);
+ create_packet(buf, payload_len1, 0, payload_len2, 0);
+ write_packet(fd, buf, total_hdr_len + payload_len2, daddr);
+}
+
+/* If incoming segments make tracked segment length exceed
+ * legal IP datagram length, do not coalesce
+ */
+static void send_large(int fd, struct sockaddr_ll *daddr, int remainder)
+{
+ static char pkts[NUM_LARGE_PKT][TOTAL_HDR_LEN + MSS];
+ static char last[TOTAL_HDR_LEN + MSS];
+ static char new_seg[TOTAL_HDR_LEN + MSS];
+ int i;
+
+ for (i = 0; i < NUM_LARGE_PKT; i++)
+ create_packet(pkts[i], i * MSS, 0, MSS, 0);
+ create_packet(last, NUM_LARGE_PKT * MSS, 0, remainder, 0);
+ create_packet(new_seg, (NUM_LARGE_PKT + 1) * MSS, 0, remainder, 0);
+
+ for (i = 0; i < NUM_LARGE_PKT; i++)
+ write_packet(fd, pkts[i], total_hdr_len + MSS, daddr);
+ write_packet(fd, last, total_hdr_len + remainder, daddr);
+ write_packet(fd, new_seg, total_hdr_len + remainder, daddr);
+}
+
+/* Pure acks and dup acks don't coalesce */
+static void send_ack(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN];
+
+ create_packet(buf, 0, 0, 0, 0);
+ write_packet(fd, buf, total_hdr_len, daddr);
+ write_packet(fd, buf, total_hdr_len, daddr);
+ create_packet(buf, 0, 1, 0, 0);
+ write_packet(fd, buf, total_hdr_len, daddr);
+}
+
+static void recompute_packet(char *buf, char *no_ext, int extlen)
+{
+ struct tcphdr *tcphdr = (struct tcphdr *)(buf + tcp_offset);
+ struct ipv6hdr *ip6h = (struct ipv6hdr *)(buf + ETH_HLEN);
+ struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+
+ memmove(buf, no_ext, total_hdr_len);
+ memmove(buf + total_hdr_len + extlen,
+ no_ext + total_hdr_len, PAYLOAD_LEN);
+
+ tcphdr->doff = tcphdr->doff + (extlen / 4);
+ tcphdr->check = 0;
+ tcphdr->check = tcp_checksum(tcphdr, PAYLOAD_LEN + extlen);
+ if (proto == PF_INET) {
+ iph->tot_len = htons(ntohs(iph->tot_len) + extlen);
+ iph->check = 0;
+ iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+ } else {
+ ip6h->payload_len = htons(ntohs(ip6h->payload_len) + extlen);
+ }
+}
+
+static void tcp_write_options(char *buf, int kind, int ts)
+{
+ struct tcp_option_ts {
+ uint8_t kind;
+ uint8_t len;
+ uint32_t tsval;
+ uint32_t tsecr;
+ } *opt_ts = (void *)buf;
+ struct tcp_option_window {
+ uint8_t kind;
+ uint8_t len;
+ uint8_t shift;
+ } *opt_window = (void *)buf;
+
+ switch (kind) {
+ case TCPOPT_NOP:
+ buf[0] = TCPOPT_NOP;
+ break;
+ case TCPOPT_WINDOW:
+ memset(opt_window, 0, sizeof(struct tcp_option_window));
+ opt_window->kind = TCPOPT_WINDOW;
+ opt_window->len = TCPOLEN_WINDOW;
+ opt_window->shift = 0;
+ break;
+ case TCPOPT_TIMESTAMP:
+ memset(opt_ts, 0, sizeof(struct tcp_option_ts));
+ opt_ts->kind = TCPOPT_TIMESTAMP;
+ opt_ts->len = TCPOLEN_TIMESTAMP;
+ opt_ts->tsval = ts;
+ opt_ts->tsecr = 0;
+ break;
+ default:
+ error(1, 0, "unimplemented TCP option");
+ break;
+ }
+}
+
+/* TCP with options is always a permutation of {TS, NOP, NOP}.
+ * Implement different orders to verify coalescing stops.
+ */
+static void add_standard_tcp_options(char *buf, char *no_ext, int ts, int order)
+{
+ switch (order) {
+ case 0:
+ tcp_write_options(buf + total_hdr_len, TCPOPT_NOP, 0);
+ tcp_write_options(buf + total_hdr_len + 1, TCPOPT_NOP, 0);
+ tcp_write_options(buf + total_hdr_len + 2 /* two NOP opts */,
+ TCPOPT_TIMESTAMP, ts);
+ break;
+ case 1:
+ tcp_write_options(buf + total_hdr_len, TCPOPT_NOP, 0);
+ tcp_write_options(buf + total_hdr_len + 1,
+ TCPOPT_TIMESTAMP, ts);
+ tcp_write_options(buf + total_hdr_len + 1 + TCPOLEN_TIMESTAMP,
+ TCPOPT_NOP, 0);
+ break;
+ case 2:
+ tcp_write_options(buf + total_hdr_len, TCPOPT_TIMESTAMP, ts);
+ tcp_write_options(buf + total_hdr_len + TCPOLEN_TIMESTAMP + 1,
+ TCPOPT_NOP, 0);
+ tcp_write_options(buf + total_hdr_len + TCPOLEN_TIMESTAMP + 2,
+ TCPOPT_NOP, 0);
+ break;
+ default:
+ error(1, 0, "unknown order");
+ break;
+ }
+ recompute_packet(buf, no_ext, TCPOLEN_TSTAMP_APPA);
+}
+
+/* Packets with invalid checksum don't coalesce. */
+static void send_changed_checksum(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ struct tcphdr *tcph = (struct tcphdr *)(buf + tcp_offset);
+ int pkt_size = total_hdr_len + PAYLOAD_LEN;
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ tcph->check = tcph->check - 1;
+ write_packet(fd, buf, pkt_size, daddr);
+}
+
+ /* Packets with non-consecutive sequence number don't coalesce.*/
+static void send_changed_seq(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ struct tcphdr *tcph = (struct tcphdr *)(buf + tcp_offset);
+ int pkt_size = total_hdr_len + PAYLOAD_LEN;
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ tcph->seq = ntohl(htonl(tcph->seq) + 1);
+ tcph->check = 0;
+ tcph->check = tcp_checksum(tcph, PAYLOAD_LEN);
+ write_packet(fd, buf, pkt_size, daddr);
+}
+
+ /* Packet with different timestamp option or different timestamps
+ * don't coalesce.
+ */
+static void send_changed_ts(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ static char extpkt[sizeof(buf) + TCPOLEN_TSTAMP_APPA];
+ int pkt_size = total_hdr_len + PAYLOAD_LEN + TCPOLEN_TSTAMP_APPA;
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt, buf, 0, 0);
+ write_packet(fd, extpkt, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt, buf, 0, 0);
+ write_packet(fd, extpkt, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt, buf, 100, 0);
+ write_packet(fd, extpkt, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 3, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt, buf, 100, 1);
+ write_packet(fd, extpkt, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 4, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt, buf, 100, 2);
+ write_packet(fd, extpkt, pkt_size, daddr);
+}
+
+/* Packet with different tcp options don't coalesce. */
+static void send_diff_opt(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ static char extpkt1[sizeof(buf) + TCPOLEN_TSTAMP_APPA];
+ static char extpkt2[sizeof(buf) + TCPOLEN_MAXSEG];
+ int extpkt1_size = total_hdr_len + PAYLOAD_LEN + TCPOLEN_TSTAMP_APPA;
+ int extpkt2_size = total_hdr_len + PAYLOAD_LEN + TCPOLEN_MAXSEG;
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt1, buf, 0, 0);
+ write_packet(fd, extpkt1, extpkt1_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ add_standard_tcp_options(extpkt1, buf, 0, 0);
+ write_packet(fd, extpkt1, extpkt1_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+ tcp_write_options(extpkt2 + MAX_HDR_LEN, TCPOPT_NOP, 0);
+ tcp_write_options(extpkt2 + MAX_HDR_LEN + 1, TCPOPT_WINDOW, 0);
+ recompute_packet(extpkt2, buf, TCPOLEN_WINDOW + 1);
+ write_packet(fd, extpkt2, extpkt2_size, daddr);
+}
+
+static void add_ipv4_ts_option(void *buf, void *optpkt)
+{
+ struct ip_timestamp *ts = (struct ip_timestamp *)(optpkt + tcp_offset);
+ int optlen = sizeof(struct ip_timestamp);
+ struct iphdr *iph;
+
+ if (optlen % 4)
+ error(1, 0, "ipv4 timestamp length is not a multiple of 4B");
+
+ ts->ipt_code = IPOPT_TS;
+ ts->ipt_len = optlen;
+ ts->ipt_ptr = 5;
+ ts->ipt_flg = IPOPT_TS_TSONLY;
+
+ memcpy(optpkt, buf, tcp_offset);
+ memcpy(optpkt + tcp_offset + optlen, buf + tcp_offset,
+ sizeof(struct tcphdr) + PAYLOAD_LEN);
+
+ iph = (struct iphdr *)(optpkt + ETH_HLEN);
+ iph->ihl = 5 + (optlen / 4);
+ iph->tot_len = htons(ntohs(iph->tot_len) + optlen);
+ iph->check = 0;
+ iph->check = checksum_fold(iph, sizeof(struct iphdr) + optlen, 0);
+}
+
+/* IPv4 options shouldn't coalesce */
+static void send_ip_options(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ static char optpkt[sizeof(buf) + sizeof(struct ip_timestamp)];
+ int optlen = sizeof(struct ip_timestamp);
+ int pkt_size = total_hdr_len + PAYLOAD_LEN + optlen;
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, total_hdr_len + PAYLOAD_LEN, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 1, 0, PAYLOAD_LEN, 0);
+ add_ipv4_ts_option(buf, optpkt);
+ write_packet(fd, optpkt, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, total_hdr_len + PAYLOAD_LEN, daddr);
+}
+
+/* IPv4 fragments shouldn't coalesce */
+static void send_fragment4(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[IP_MAXPACKET];
+ struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+ int pkt_size = total_hdr_len + PAYLOAD_LEN;
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, pkt_size, daddr);
+
+ /* Once fragmented, packet would retain the total_len.
+ * Tcp header is prepared as if rest of data is in follow-up frags,
+ * but follow up frags aren't actually sent.
+ */
+ memset(buf + total_hdr_len, 'a', PAYLOAD_LEN * 2);
+ fill_transportlayer(buf + tcp_offset, PAYLOAD_LEN, 0, PAYLOAD_LEN * 2, 0);
+ fill_networklayer(buf + ETH_HLEN, PAYLOAD_LEN);
+ fill_datalinklayer(buf);
+
+ iph->frag_off = htons(0x6000); // DF = 1, MF = 1
+ iph->check = 0;
+ iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+ write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* IPv4 packets with different ttl don't coalesce.*/
+static void send_changed_ttl(int fd, struct sockaddr_ll *daddr)
+{
+ int pkt_size = total_hdr_len + PAYLOAD_LEN;
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ iph->ttl = 7;
+ iph->check = 0;
+ iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+ write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* Packets with different tos don't coalesce.*/
+static void send_changed_tos(int fd, struct sockaddr_ll *daddr)
+{
+ int pkt_size = total_hdr_len + PAYLOAD_LEN;
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+ struct ipv6hdr *ip6h = (struct ipv6hdr *)(buf + ETH_HLEN);
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ if (proto == PF_INET) {
+ iph->tos = 1;
+ iph->check = 0;
+ iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+ } else if (proto == PF_INET6) {
+ ip6h->priority = 0xf;
+ }
+ write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* Packets with different ECN don't coalesce.*/
+static void send_changed_ECN(int fd, struct sockaddr_ll *daddr)
+{
+ int pkt_size = total_hdr_len + PAYLOAD_LEN;
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, pkt_size, daddr);
+
+ create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+ if (proto == PF_INET) {
+ buf[ETH_HLEN + 1] ^= 0x2; // ECN set to 10
+ iph->check = 0;
+ iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+ } else {
+ buf[ETH_HLEN + 1] ^= 0x20; // ECN set to 10
+ }
+ write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* IPv6 fragments and packets with extensions don't coalesce.*/
+static void send_fragment6(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ static char extpkt[MAX_HDR_LEN + PAYLOAD_LEN +
+ sizeof(struct ip6_frag)];
+ struct ipv6hdr *ip6h = (struct ipv6hdr *)(buf + ETH_HLEN);
+ struct ip6_frag *frag = (void *)(extpkt + tcp_offset);
+ int extlen = sizeof(struct ip6_frag);
+ int bufpkt_len = total_hdr_len + PAYLOAD_LEN;
+ int extpkt_len = bufpkt_len + extlen;
+ int i;
+
+ for (i = 0; i < 2; i++) {
+ create_packet(buf, PAYLOAD_LEN * i, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, bufpkt_len, daddr);
+ }
+
+ create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+ memset(extpkt, 0, extpkt_len);
+
+ ip6h->nexthdr = IPPROTO_FRAGMENT;
+ ip6h->payload_len = htons(ntohs(ip6h->payload_len) + extlen);
+ frag->ip6f_nxt = IPPROTO_TCP;
+
+ memcpy(extpkt, buf, tcp_offset);
+ memcpy(extpkt + tcp_offset + extlen, buf + tcp_offset,
+ sizeof(struct tcphdr) + PAYLOAD_LEN);
+ write_packet(fd, extpkt, extpkt_len, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 3, 0, PAYLOAD_LEN, 0);
+ write_packet(fd, buf, bufpkt_len, daddr);
+}
+
+static void bind_packetsocket(int fd)
+{
+ struct sockaddr_ll daddr = {};
+
+ daddr.sll_family = AF_PACKET;
+ daddr.sll_protocol = ethhdr_proto;
+ daddr.sll_ifindex = if_nametoindex(ifname);
+ if (daddr.sll_ifindex == 0)
+ error(1, errno, "if_nametoindex");
+
+ if (bind(fd, (void *)&daddr, sizeof(daddr)) < 0)
+ error(1, errno, "could not bind socket");
+}
+
+static void set_timeout(int fd)
+{
+ struct timeval timeout;
+
+ timeout.tv_sec = 3;
+ timeout.tv_usec = 0;
+ if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout,
+ sizeof(timeout)) < 0)
+ error(1, errno, "cannot set timeout, setsockopt failed");
+}
+
+static void check_recv_pkts(int fd, int *correct_payload,
+ int correct_num_pkts)
+{
+ static char buffer[IP_MAXPACKET + ETH_HLEN + 1];
+ struct iphdr *iph = (struct iphdr *)(buffer + ETH_HLEN);
+ struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + ETH_HLEN);
+ struct tcphdr *tcph;
+ bool bad_packet = false;
+ int tcp_ext_len = 0;
+ int ip_ext_len = 0;
+ int pkt_size = -1;
+ int data_len = 0;
+ int num_pkt = 0;
+ int i;
+
+ vlog("Expected {");
+ for (i = 0; i < correct_num_pkts; i++)
+ vlog("%d ", correct_payload[i]);
+ vlog("}, Total %d packets\nReceived {", correct_num_pkts);
+
+ while (1) {
+ pkt_size = recv(fd, buffer, IP_MAXPACKET + ETH_HLEN + 1, 0);
+ if (pkt_size < 0)
+ error(1, errno, "could not receive");
+
+ if (iph->version == 4)
+ ip_ext_len = (iph->ihl - 5) * 4;
+ else if (ip6h->version == 6 && ip6h->nexthdr != IPPROTO_TCP)
+ ip_ext_len = sizeof(struct ip6_frag);
+
+ tcph = (struct tcphdr *)(buffer + tcp_offset + ip_ext_len);
+
+ if (tcph->fin)
+ break;
+
+ tcp_ext_len = (tcph->doff - 5) * 4;
+ data_len = pkt_size - total_hdr_len - tcp_ext_len - ip_ext_len;
+ /* Min ethernet frame payload is 46(ETH_ZLEN - ETH_HLEN) by RFC 802.3.
+ * Ipv4/tcp packets without at least 6 bytes of data will be padded.
+ * Packet sockets are protocol agnostic, and will not trim the padding.
+ */
+ if (pkt_size == ETH_ZLEN && iph->version == 4) {
+ data_len = ntohs(iph->tot_len)
+ - sizeof(struct tcphdr) - sizeof(struct iphdr);
+ }
+ vlog("%d ", data_len);
+ if (data_len != correct_payload[num_pkt]) {
+ vlog("[!=%d]", correct_payload[num_pkt]);
+ bad_packet = true;
+ }
+ num_pkt++;
+ }
+ vlog("}, Total %d packets.\n", num_pkt);
+ if (num_pkt != correct_num_pkts)
+ error(1, 0, "incorrect number of packets");
+ if (bad_packet)
+ error(1, 0, "incorrect packet geometry");
+
+ printf("Test succeeded\n\n");
+}
+
+static void gro_sender(void)
+{
+ static char fin_pkt[MAX_HDR_LEN];
+ struct sockaddr_ll daddr = {};
+ int txfd = -1;
+
+ txfd = socket(PF_PACKET, SOCK_RAW, IPPROTO_RAW);
+ if (txfd < 0)
+ error(1, errno, "socket creation");
+
+ memset(&daddr, 0, sizeof(daddr));
+ daddr.sll_ifindex = if_nametoindex(ifname);
+ if (daddr.sll_ifindex == 0)
+ error(1, errno, "if_nametoindex");
+ daddr.sll_family = AF_PACKET;
+ memcpy(daddr.sll_addr, dst_mac, ETH_ALEN);
+ daddr.sll_halen = ETH_ALEN;
+ create_packet(fin_pkt, PAYLOAD_LEN * 2, 0, 0, 1);
+
+ if (strcmp(testname, "data") == 0) {
+ send_data_pkts(txfd, &daddr, PAYLOAD_LEN, PAYLOAD_LEN);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_data_pkts(txfd, &daddr, PAYLOAD_LEN, PAYLOAD_LEN / 2);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_data_pkts(txfd, &daddr, PAYLOAD_LEN / 2, PAYLOAD_LEN);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ } else if (strcmp(testname, "ack") == 0) {
+ send_ack(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ } else if (strcmp(testname, "flags") == 0) {
+ send_flags(txfd, &daddr, 1, 0, 0, 0);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_flags(txfd, &daddr, 0, 1, 0, 0);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_flags(txfd, &daddr, 0, 0, 1, 0);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_flags(txfd, &daddr, 0, 0, 0, 1);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ } else if (strcmp(testname, "tcp") == 0) {
+ send_changed_checksum(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_changed_seq(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_changed_ts(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_diff_opt(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ } else if (strcmp(testname, "ip") == 0) {
+ send_changed_ECN(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_changed_tos(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ if (proto == PF_INET) {
+ /* Modified packets may be received out of order.
+ * Sleep function added to enforce test boundaries
+ * so that fin pkts are not received prior to other pkts.
+ */
+ sleep(1);
+ send_changed_ttl(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ sleep(1);
+ send_ip_options(txfd, &daddr);
+ sleep(1);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ sleep(1);
+ send_fragment4(txfd, &daddr);
+ sleep(1);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ } else if (proto == PF_INET6) {
+ send_fragment6(txfd, &daddr);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ }
+ } else if (strcmp(testname, "large") == 0) {
+ /* 20 is the difference between min iphdr size
+ * and min ipv6hdr size. Like MAX_HDR_SIZE,
+ * MAX_PAYLOAD is defined with the larger header of the two.
+ */
+ int offset = proto == PF_INET ? 20 : 0;
+ int remainder = (MAX_PAYLOAD + offset) % MSS;
+
+ send_large(txfd, &daddr, remainder);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ send_large(txfd, &daddr, remainder + 1);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+ } else {
+ error(1, 0, "Unknown testcase");
+ }
+
+ if (close(txfd))
+ error(1, errno, "socket close");
+}
+
+static void gro_receiver(void)
+{
+ static int correct_payload[NUM_PACKETS];
+ int rxfd = -1;
+
+ rxfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_NONE));
+ if (rxfd < 0)
+ error(1, 0, "socket creation");
+ setup_sock_filter(rxfd);
+ set_timeout(rxfd);
+ bind_packetsocket(rxfd);
+
+ memset(correct_payload, 0, sizeof(correct_payload));
+
+ if (strcmp(testname, "data") == 0) {
+ printf("pure data packet of same size: ");
+ correct_payload[0] = PAYLOAD_LEN * 2;
+ check_recv_pkts(rxfd, correct_payload, 1);
+
+ printf("large data packets followed by a smaller one: ");
+ correct_payload[0] = PAYLOAD_LEN * 1.5;
+ check_recv_pkts(rxfd, correct_payload, 1);
+
+ printf("small data packets followed by a larger one: ");
+ correct_payload[0] = PAYLOAD_LEN / 2;
+ correct_payload[1] = PAYLOAD_LEN;
+ check_recv_pkts(rxfd, correct_payload, 2);
+ } else if (strcmp(testname, "ack") == 0) {
+ printf("duplicate ack and pure ack: ");
+ check_recv_pkts(rxfd, correct_payload, 3);
+ } else if (strcmp(testname, "flags") == 0) {
+ correct_payload[0] = PAYLOAD_LEN * 3;
+ correct_payload[1] = PAYLOAD_LEN * 2;
+
+ printf("psh flag ends coalescing: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ correct_payload[0] = PAYLOAD_LEN * 2;
+ correct_payload[1] = 0;
+ correct_payload[2] = PAYLOAD_LEN * 2;
+ printf("syn flag ends coalescing: ");
+ check_recv_pkts(rxfd, correct_payload, 3);
+
+ printf("rst flag ends coalescing: ");
+ check_recv_pkts(rxfd, correct_payload, 3);
+
+ printf("urg flag ends coalescing: ");
+ check_recv_pkts(rxfd, correct_payload, 3);
+ } else if (strcmp(testname, "tcp") == 0) {
+ correct_payload[0] = PAYLOAD_LEN;
+ correct_payload[1] = PAYLOAD_LEN;
+ correct_payload[2] = PAYLOAD_LEN;
+ correct_payload[3] = PAYLOAD_LEN;
+
+ printf("changed checksum does not coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ printf("Wrong Seq number doesn't coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ printf("Different timestamp doesn't coalesce: ");
+ correct_payload[0] = PAYLOAD_LEN * 2;
+ check_recv_pkts(rxfd, correct_payload, 4);
+
+ printf("Different options doesn't coalesce: ");
+ correct_payload[0] = PAYLOAD_LEN * 2;
+ check_recv_pkts(rxfd, correct_payload, 2);
+ } else if (strcmp(testname, "ip") == 0) {
+ correct_payload[0] = PAYLOAD_LEN;
+ correct_payload[1] = PAYLOAD_LEN;
+
+ printf("different ECN doesn't coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ printf("different tos doesn't coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ if (proto == PF_INET) {
+ printf("different ttl doesn't coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ printf("ip options doesn't coalesce: ");
+ correct_payload[2] = PAYLOAD_LEN;
+ check_recv_pkts(rxfd, correct_payload, 3);
+
+ printf("fragmented ip4 doesn't coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+ } else if (proto == PF_INET6) {
+ /* GRO doesn't check for ipv6 hop limit when flushing.
+ * Hence no corresponding test to the ipv4 case.
+ */
+ printf("fragmented ip6 doesn't coalesce: ");
+ correct_payload[0] = PAYLOAD_LEN * 2;
+ check_recv_pkts(rxfd, correct_payload, 2);
+ }
+ } else if (strcmp(testname, "large") == 0) {
+ int offset = proto == PF_INET ? 20 : 0;
+ int remainder = (MAX_PAYLOAD + offset) % MSS;
+
+ correct_payload[0] = (MAX_PAYLOAD + offset);
+ correct_payload[1] = remainder;
+ printf("Shouldn't coalesce if exceed IP max pkt size: ");
+ check_recv_pkts(rxfd, correct_payload, 2);
+
+ /* last segment sent individually, doesn't start new segment */
+ correct_payload[0] = correct_payload[0] - remainder;
+ correct_payload[1] = remainder + 1;
+ correct_payload[2] = remainder + 1;
+ check_recv_pkts(rxfd, correct_payload, 3);
+ } else {
+ error(1, 0, "Test case error, should never trigger");
+ }
+
+ if (close(rxfd))
+ error(1, 0, "socket close");
+}
+
+static void parse_args(int argc, char **argv)
+{
+ static const struct option opts[] = {
+ { "daddr", required_argument, NULL, 'd' },
+ { "dmac", required_argument, NULL, 'D' },
+ { "iface", required_argument, NULL, 'i' },
+ { "ipv4", no_argument, NULL, '4' },
+ { "ipv6", no_argument, NULL, '6' },
+ { "rx", no_argument, NULL, 'r' },
+ { "saddr", required_argument, NULL, 's' },
+ { "smac", required_argument, NULL, 'S' },
+ { "test", required_argument, NULL, 't' },
+ { "verbose", no_argument, NULL, 'v' },
+ { 0, 0, 0, 0 }
+ };
+ int c;
+
+ while ((c = getopt_long(argc, argv, "46d:D:i:rs:S:t:v", opts, NULL)) != -1) {
+ switch (c) {
+ case '4':
+ proto = PF_INET;
+ ethhdr_proto = htons(ETH_P_IP);
+ break;
+ case '6':
+ proto = PF_INET6;
+ ethhdr_proto = htons(ETH_P_IPV6);
+ break;
+ case 'd':
+ addr4_dst = addr6_dst = optarg;
+ break;
+ case 'D':
+ dmac = optarg;
+ break;
+ case 'i':
+ ifname = optarg;
+ break;
+ case 'r':
+ tx_socket = false;
+ break;
+ case 's':
+ addr4_src = addr6_src = optarg;
+ break;
+ case 'S':
+ smac = optarg;
+ break;
+ case 't':
+ testname = optarg;
+ break;
+ case 'v':
+ verbose = true;
+ break;
+ default:
+ error(1, 0, "%s invalid option %c\n", __func__, c);
+ break;
+ }
+ }
+}
+
+int main(int argc, char **argv)
+{
+ parse_args(argc, argv);
+
+ if (proto == PF_INET) {
+ tcp_offset = ETH_HLEN + sizeof(struct iphdr);
+ total_hdr_len = tcp_offset + sizeof(struct tcphdr);
+ } else if (proto == PF_INET6) {
+ tcp_offset = ETH_HLEN + sizeof(struct ipv6hdr);
+ total_hdr_len = MAX_HDR_LEN;
+ } else {
+ error(1, 0, "Protocol family is not ipv4 or ipv6");
+ }
+
+ read_MAC(src_mac, smac);
+ read_MAC(dst_mac, dmac);
+
+ if (tx_socket)
+ gro_sender();
+ else
+ gro_receiver();
+
+ fprintf(stderr, "Gro::%s test passed.\n", testname);
+ return 0;
+}