From d303cfdd55a7fb30bedd1727216e0a3926c4a95c Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Fri, 21 May 2021 11:14:50 +0200 Subject: icmp: Implement ping tracking based on echo identifiers Open and bind a socket for each possible ICMP/ICMPv6 echo identifier, and add a tracking mechanism. Otherwise, multiple pings in parallel won't work, and a single ping to a different destination would make an existing ping sequence stop working. Signed-off-by: Stefano Brivio --- icmp.c | 57 +++++++++++++++++++++++++++++++++------------------------ icmp.h | 4 ---- util.c | 3 --- 3 files changed, 33 insertions(+), 31 deletions(-) diff --git a/icmp.c b/icmp.c index 3423856..08e7324 100644 --- a/icmp.c +++ b/icmp.c @@ -33,6 +33,10 @@ #include "util.h" #include "icmp.h" +/* Indexed by ICMP echo identifier */ +static int icmp_s_v4[USHRT_MAX]; +static int icmp_s_v6[USHRT_MAX]; + /** * icmp_sock_handler() - Handle new data from socket * @c: Execution context @@ -91,48 +95,43 @@ void icmp_sock_handler(struct ctx *c, int s, uint32_t events, char *pkt_buf, int icmp_tap_handler(struct ctx *c, int af, void *addr, struct tap_msg *msg, int count, struct timespec *now) { + int s; + (void)count; (void)now; + (void)c; if (af == AF_INET) { struct icmphdr *ih = (struct icmphdr *)msg[0].l4h; struct sockaddr_in sa = { .sin_family = AF_INET, - .sin_addr.s_addr = htonl(INADDR_ANY), + .sin_addr = *(struct in_addr *)addr, }; - if (c->icmp.s4 < 0) - return 1; - if (msg[0].l4_len < sizeof(*ih) || ih->type != ICMP_ECHO) return 1; - sa.sin_port = ih->un.echo.id; - bind(c->icmp.s4, (struct sockaddr *)&sa, sizeof(sa)); + if ((s = icmp_s_v4[ntohs(ih->un.echo.id)]) < 0) + return 1; - sa.sin_addr = *(struct in_addr *)addr; - sendto(c->icmp.s4, msg[0].l4h, msg[0].l4_len, + sendto(s, msg[0].l4h, msg[0].l4_len, MSG_DONTWAIT | MSG_NOSIGNAL, (struct sockaddr *)&sa, sizeof(sa)); } else if (af == AF_INET6) { + struct icmp6hdr *ih = (struct icmp6hdr *)msg[0].l4h; struct sockaddr_in6 sa = { .sin6_family = AF_INET6, - .sin6_addr = IN6ADDR_ANY_INIT, + .sin6_addr = *(struct in6_addr *)addr, }; - struct icmp6hdr *ih = (struct icmp6hdr *)msg[0].l4h; - - if (c->icmp.s6 < 0) - return 1; if (msg[0].l4_len < sizeof(*ih) || (ih->icmp6_type != 128 && ih->icmp6_type != 129)) return 1; - sa.sin6_port = ih->icmp6_identifier; - bind(c->icmp.s6, (struct sockaddr *)&sa, sizeof(sa)); + if ((s = icmp_s_v6[ntohs(ih->icmp6_identifier)]) < 0) + return 1; - sa.sin6_addr = *(struct in6_addr *)addr; - sendto(c->icmp.s6, msg[0].l4h, msg[0].l4_len, + sendto(s, msg[0].l4h, msg[0].l4_len, MSG_DONTWAIT | MSG_NOSIGNAL, (struct sockaddr *)&sa, sizeof(sa)); } @@ -148,21 +147,31 @@ int icmp_tap_handler(struct ctx *c, int af, void *addr, */ int icmp_sock_init(struct ctx *c) { - int fail = 0; + int i, fail = 0; c->icmp.fd_min = INT_MAX; c->icmp.fd_max = 0; - if (c->v4 && (c->icmp.s4 = sock_l4(c, AF_INET, IPPROTO_ICMP, 0)) < 0) - fail = 1; + if (c->v4) { + for (i = 0; i < USHRT_MAX; i++) { + icmp_s_v4[i] = sock_l4(c, AF_INET, IPPROTO_ICMP, i); + if (icmp_s_v4[i] < 0) + fail = 1; + } + } - if (c->v6 && (c->icmp.s6 = sock_l4(c, AF_INET6, IPPROTO_ICMPV6, 0)) < 0) - fail = 1; + if (c->v6) { + for (i = 0; i < USHRT_MAX; i++) { + icmp_s_v6[i] = sock_l4(c, AF_INET6, IPPROTO_ICMPV6, i); + if (icmp_s_v6[i] < 0) + fail = 1; + } + } if (fail) { - warn("Cannot open \"ping\" socket. You might need to:"); + warn("Cannot open some \"ping\" sockets. You might need to:"); warn(" sysctl -w net.ipv4.ping_group_range=\"0 2147483647\""); - warn("...continuing without echo request/reply support."); + warn("...echo requests/replies might fail."); } return 0; diff --git a/icmp.h b/icmp.h index 4152b7e..d04eb8c 100644 --- a/icmp.h +++ b/icmp.h @@ -11,14 +11,10 @@ int icmp_sock_init(struct ctx *c); /** * struct icmp_ctx - Execution context for ICMP routines - * @s4: ICMP socket number - * @s6: ICMPv6 socket number * @fd_min: Lowest file descriptor number for ICMP/ICMPv6 ever used * @fd_max: Highest file descriptor number for ICMP/ICMPv6 ever used */ struct icmp_ctx { - int s4; - int s6; int fd_min; int fd_max; }; diff --git a/util.c b/util.c index 9ccd9f6..9748cbe 100644 --- a/util.c +++ b/util.c @@ -189,9 +189,6 @@ int sock_l4(struct ctx *c, int af, uint16_t proto, uint16_t port) return -1; } - if (proto == IPPROTO_ICMP || proto == IPPROTO_ICMPV6) - goto epoll_add; - if (af == AF_INET) { sa = (const struct sockaddr *)&addr4; sl = sizeof(addr4); -- cgit v1.2.3