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Diffstat (limited to 'src/ip_icmp_ping.c')
| -rw-r--r-- | src/ip_icmp_ping.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/src/ip_icmp_ping.c b/src/ip_icmp_ping.c new file mode 100644 index 0000000..a666248 --- /dev/null +++ b/src/ip_icmp_ping.c @@ -0,0 +1,118 @@ +/* + * Copyright (c) 2017 + * Google Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + */ + +/* + * Support ping using the system ping binary on Linux and Mac + * On Linux/Mac, icmp protocol requires the process to have system permission. + * Our emulator, by default, does not have system permission, so we have to + * resort to the built-in ping binary to handle icmp messages. + */ + +#include "slirp.h" +#include "ip_icmp.h" + +#include <fcntl.h> + +int ping_binary_send(struct socket* so, struct mbuf* m, int hlen) { + struct ip* ip = mtod(m, struct ip*); + const char* dest_ip_addr = inet_ntoa(ip->ip_dst); + char ping_cmd[1024]; + sprintf(ping_cmd, "ping -c 1 -t %d %s 2>&1", ip->ip_ttl, dest_ip_addr); + FILE* p = popen(ping_cmd, "r"); + if (!p) { + DEBUG_ERROR("popen failed for ping binary"); + return -1; + } + + so->ping_pipe = p; + + // this is rather critical, otherwise emulator blocks when pinging + // an unreachable host + so->s = fileno(p); + fcntl(so->s, F_SETFL, O_NONBLOCK); + + return 0; +} + +/* +ping -c 1 www.google.com +PING www.google.com (172.217.6.36) 56(84) bytes of data. +64 bytes from sfo03s08-in-f36.1e100.net (172.217.6.36): icmp_seq=1 ttl=57 +time=1.31 ms + +--- www.google.com ping statistics --- +1 packets transmitted, 1 received, 0% packet loss, time 0ms +rtt min/avg/max/mdev = 1.316/1.316/1.316/0.000 ms +*/ +int ping_binary_recv(struct socket* so, struct ip* ip, struct icmp* icp) { + if (so == NULL || so->ping_pipe == NULL) { + return -1; + } + + int seq = -1, ttl = -1; + char line[4096] = ""; + char skip[4096] = ""; + char skip2[4096] = ""; + while (fgets(line, sizeof(line), so->ping_pipe)) { + char* p = strstr(line, "icmp_seq="); + if (p != NULL) { + p += strlen("icmp_seq="); + seq = atoi(p); + } + p = strstr(line, "ttl="); + if (p != NULL) { + p += strlen("ttl="); + ttl = atoi(p); + } + + if (seq != -1 && ttl != -1) { + break; + } + } + + if (seq != -1 && ttl != -1) { + ip->ip_ttl = ttl; + ip->ip_p = IPPROTO_ICMP; + icp->icmp_type = ICMP_ECHOREPLY; + icp->icmp_code = 0; + icp->icmp_cksum = 0; + // icp->icmp_seq = seq; + return sizeof(*icp); + } + + return -1; +} + +void ping_binary_close(struct socket* so) { + if (so != NULL && so->ping_pipe) { + pclose(so->ping_pipe); + so->ping_pipe = NULL; + } +} |