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https://passt.top/passt
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e07f539ae0
This is in preparation for scatter-gather IO on the UDP receive path: save a getsockname() syscall by setting a flag if we get the numbering of all bound sockets in a strict sequence (expected, in practice) and repurpose the tap buffer to be also a socket receive buffer, passing it down to protocol handlers. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
156 lines
3.8 KiB
C
156 lines
3.8 KiB
C
// SPDX-License-Identifier: AGPL-3.0-or-later
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/* PASST - Plug A Simple Socket Transport
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*
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* icmp.c - ICMP/ICMPv6 echo proxy
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*
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <limits.h>
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#include <net/ethernet.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <stdint.h>
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#include <stddef.h>
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#include <string.h>
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#include <sys/epoll.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/icmp.h>
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#include <linux/icmpv6.h>
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#include <time.h>
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#include "passt.h"
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#include "tap.h"
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#include "util.h"
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#include "icmp.h"
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/**
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* icmp_sock_handler() - Handle new data from socket
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* @c: Execution context
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* @s: File descriptor number for socket
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* @events: epoll events bitmap
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* @pkt_buf: Buffer to receive packets, currently unused
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* @now: Current timestamp, unused
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*/
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void icmp_sock_handler(struct ctx *c, int s, uint32_t events, char *pkt_buf,
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struct timespec *now)
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{
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struct in6_addr a6 = { .s6_addr = { 0, 0, 0, 0,
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0, 0, 0, 0,
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0, 0, 0xff, 0xff,
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0, 0, 0, 0 } };
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struct sockaddr_storage sr, sl;
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socklen_t slen = sizeof(sr);
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char buf[USHRT_MAX];
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ssize_t n;
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(void)events;
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(void)pkt_buf;
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(void)now;
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n = recvfrom(s, buf, sizeof(buf), MSG_DONTWAIT,
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(struct sockaddr *)&sr, &slen);
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if (n < 0)
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return;
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if (getsockname(s, (struct sockaddr *)&sl, &slen))
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return;
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if (sl.ss_family == AF_INET) {
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struct sockaddr_in *sr4 = (struct sockaddr_in *)&sr;
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memcpy(&a6.s6_addr[12], &sr4->sin_addr, sizeof(sr4->sin_addr));
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tap_ip_send(c, &a6, IPPROTO_ICMP, buf, n);
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} else if (sl.ss_family == AF_INET6) {
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struct sockaddr_in6 *sr6 = (struct sockaddr_in6 *)&sr;
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tap_ip_send(c, &sr6->sin6_addr, IPPROTO_ICMPV6, buf, n);
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}
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}
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/**
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* icmp_tap_handler() - Handle packets from tap
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* @c: Execution context
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* @af: Address family, AF_INET or AF_INET6
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* @msg: Input message
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* @count: Message count (always 1 for ICMP)
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* @now: Current timestamp, unused
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*
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* Return: count of consumed packets (always 1, even if malformed)
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*/
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int icmp_tap_handler(struct ctx *c, int af, void *addr,
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struct tap_msg *msg, int count, struct timespec *now)
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{
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(void)count;
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(void)now;
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if (af == AF_INET) {
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struct icmphdr *ih = (struct icmphdr *)msg[0].l4h;
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struct sockaddr_in sa = {
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.sin_family = AF_INET,
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.sin_addr.s_addr = htonl(INADDR_ANY),
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};
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if (msg[0].l4_len < sizeof(*ih) || ih->type != ICMP_ECHO)
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return 1;
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sa.sin_port = ih->un.echo.id;
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bind(c->icmp.s4, (struct sockaddr *)&sa, sizeof(sa));
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sa.sin_addr = *(struct in_addr *)addr;
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sendto(c->icmp.s4, msg[0].l4h, msg[0].l4_len,
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MSG_DONTWAIT | MSG_NOSIGNAL,
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(struct sockaddr *)&sa, sizeof(sa));
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} else if (af == AF_INET6) {
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struct sockaddr_in6 sa = {
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.sin6_family = AF_INET6,
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.sin6_addr = IN6ADDR_ANY_INIT,
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};
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struct icmp6hdr *ih = (struct icmp6hdr *)msg[0].l4h;
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if (msg[0].l4_len < sizeof(*ih) ||
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(ih->icmp6_type != 128 && ih->icmp6_type != 129))
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return 1;
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sa.sin6_port = ih->icmp6_identifier;
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bind(c->icmp.s6, (struct sockaddr *)&sa, sizeof(sa));
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sa.sin6_addr = *(struct in6_addr *)addr;
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sendto(c->icmp.s6, msg[0].l4h, msg[0].l4_len,
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MSG_DONTWAIT | MSG_NOSIGNAL,
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(struct sockaddr *)&sa, sizeof(sa));
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}
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return 1;
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}
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/**
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* icmp_sock_init() - Create ICMP, ICMPv6 sockets for echo requests and replies
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* @c: Execution context
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*
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* Return: 0 on success, -1 on failure
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*/
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int icmp_sock_init(struct ctx *c)
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{
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c->icmp.fd_min = INT_MAX;
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c->icmp.fd_max = 0;
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if (c->v4 && (c->icmp.s4 = sock_l4(c, AF_INET, IPPROTO_ICMP, 0)) < 0)
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return -1;
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if (c->v6 && (c->icmp.s6 = sock_l4(c, AF_INET6, IPPROTO_ICMPV6, 0)) < 0)
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return -1;
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return 0;
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}
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