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Diffstat (limited to 'udp.c')
-rw-r--r--udp.c146
1 files changed, 133 insertions, 13 deletions
diff --git a/udp.c b/udp.c
index 923cc38..80520cb 100644
--- a/udp.c
+++ b/udp.c
@@ -87,6 +87,8 @@
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/icmp6.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
@@ -112,6 +114,12 @@
#include "udp_internal.h"
#include "udp_vu.h"
+/* Maximum UDP data to be returned in ICMP messages */
+#define ICMP4_MAX_DLEN 8
+#define ICMP6_MAX_DLEN (IPV6_MIN_MTU \
+ - sizeof(struct udphdr) \
+ - sizeof(struct ipv6hdr))
+
/* "Spliced" sockets indexed by bound port (host order) */
static int udp_splice_ns [IP_VERSIONS][NUM_PORTS];
static int udp_splice_init[IP_VERSIONS][NUM_PORTS];
@@ -403,24 +411,120 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
}
/**
+ * udp_send_conn_fail_icmp4() - Construct and send ICMPv4 to local peer
+ * @c: Execution context
+ * @ee: Extended error descriptor
+ * @toside: Destination side of flow
+ * @saddr: Address of ICMP generating node
+ * @in: First bytes (max 8) of original UDP message body
+ * @dlen: Length of the read part of original UDP message body
+ */
+static void udp_send_conn_fail_icmp4(const struct ctx *c,
+ const struct sock_extended_err *ee,
+ const struct flowside *toside,
+ struct in_addr saddr,
+ const void *in, size_t dlen)
+{
+ struct in_addr oaddr = toside->oaddr.v4mapped.a4;
+ struct in_addr eaddr = toside->eaddr.v4mapped.a4;
+ in_port_t eport = toside->eport;
+ in_port_t oport = toside->oport;
+ struct {
+ struct icmphdr icmp4h;
+ struct iphdr ip4h;
+ struct udphdr uh;
+ char data[ICMP4_MAX_DLEN];
+ } __attribute__((packed, aligned(__alignof__(max_align_t)))) msg;
+ size_t msglen = sizeof(msg) - sizeof(msg.data) + dlen;
+ size_t l4len = dlen + sizeof(struct udphdr);
+
+ ASSERT(dlen <= ICMP4_MAX_DLEN);
+ memset(&msg, 0, sizeof(msg));
+ msg.icmp4h.type = ee->ee_type;
+ msg.icmp4h.code = ee->ee_code;
+ if (ee->ee_type == ICMP_DEST_UNREACH && ee->ee_code == ICMP_FRAG_NEEDED)
+ msg.icmp4h.un.frag.mtu = htons((uint16_t) ee->ee_info);
+
+ /* Reconstruct the original headers as returned in the ICMP message */
+ tap_push_ip4h(&msg.ip4h, eaddr, oaddr, l4len, IPPROTO_UDP);
+ tap_push_uh4(&msg.uh, eaddr, eport, oaddr, oport, in, dlen);
+ memcpy(&msg.data, in, dlen);
+
+ tap_icmp4_send(c, saddr, eaddr, &msg, msglen);
+}
+
+
+/**
+ * udp_send_conn_fail_icmp6() - Construct and send ICMPv6 to local peer
+ * @c: Execution context
+ * @ee: Extended error descriptor
+ * @toside: Destination side of flow
+ * @saddr: Address of ICMP generating node
+ * @in: First bytes (max 1232) of original UDP message body
+ * @dlen: Length of the read part of original UDP message body
+ * @flow: IPv6 flow identifier
+ */
+static void udp_send_conn_fail_icmp6(const struct ctx *c,
+ const struct sock_extended_err *ee,
+ const struct flowside *toside,
+ const struct in6_addr *saddr,
+ void *in, size_t dlen, uint32_t flow)
+{
+ const struct in6_addr *oaddr = &toside->oaddr.a6;
+ const struct in6_addr *eaddr = &toside->eaddr.a6;
+ in_port_t eport = toside->eport;
+ in_port_t oport = toside->oport;
+ struct {
+ struct icmp6_hdr icmp6h;
+ struct ipv6hdr ip6h;
+ struct udphdr uh;
+ char data[ICMP6_MAX_DLEN];
+ } __attribute__((packed, aligned(__alignof__(max_align_t)))) msg;
+ size_t msglen = sizeof(msg) - sizeof(msg.data) + dlen;
+ size_t l4len = dlen + sizeof(struct udphdr);
+
+ ASSERT(dlen <= ICMP6_MAX_DLEN);
+ memset(&msg, 0, sizeof(msg));
+ msg.icmp6h.icmp6_type = ee->ee_type;
+ msg.icmp6h.icmp6_code = ee->ee_code;
+ if (ee->ee_type == ICMP6_PACKET_TOO_BIG)
+ msg.icmp6h.icmp6_dataun.icmp6_un_data32[0] = htonl(ee->ee_info);
+
+ /* Reconstruct the original headers as returned in the ICMP message */
+ tap_push_ip6h(&msg.ip6h, eaddr, oaddr, l4len, IPPROTO_UDP, flow);
+ tap_push_uh6(&msg.uh, eaddr, eport, oaddr, oport, in, dlen);
+ memcpy(&msg.data, in, dlen);
+
+ tap_icmp6_send(c, saddr, eaddr, &msg, msglen);
+}
+
+/**
* udp_sock_recverr() - Receive and clear an error from a socket
- * @s: Socket to receive from
+ * @c: Execution context
+ * @ref: epoll reference
*
* Return: 1 if error received and processed, 0 if no more errors in queue, < 0
* if there was an error reading the queue
*
* #syscalls recvmsg
*/
-static int udp_sock_recverr(int s)
+static int udp_sock_recverr(const struct ctx *c, union epoll_ref ref)
{
const struct sock_extended_err *ee;
const struct cmsghdr *hdr;
+ union sockaddr_inany saddr;
char buf[CMSG_SPACE(sizeof(*ee))];
+ char data[ICMP6_MAX_DLEN];
+ int s = ref.fd;
+ struct iovec iov = {
+ .iov_base = data,
+ .iov_len = sizeof(data)
+ };
struct msghdr mh = {
- .msg_name = NULL,
- .msg_namelen = 0,
- .msg_iov = NULL,
- .msg_iovlen = 0,
+ .msg_name = &saddr,
+ .msg_namelen = sizeof(saddr),
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
.msg_control = buf,
.msg_controllen = sizeof(buf),
};
@@ -450,8 +554,23 @@ static int udp_sock_recverr(int s)
}
ee = (const struct sock_extended_err *)CMSG_DATA(hdr);
-
- /* TODO: When possible propagate and otherwise handle errors */
+ if (ref.type == EPOLL_TYPE_UDP_REPLY) {
+ flow_sidx_t sidx = flow_sidx_opposite(ref.flowside);
+ const struct flowside *toside = flowside_at_sidx(sidx);
+ size_t dlen = rc;
+
+ if (hdr->cmsg_level == IPPROTO_IP) {
+ dlen = MIN(dlen, ICMP4_MAX_DLEN);
+ udp_send_conn_fail_icmp4(c, ee, toside, saddr.sa4.sin_addr,
+ data, dlen);
+ } else if (hdr->cmsg_level == IPPROTO_IPV6) {
+ udp_send_conn_fail_icmp6(c, ee, toside,
+ &saddr.sa6.sin6_addr,
+ data, dlen, sidx.flowi);
+ }
+ } else {
+ trace("Ignoring received IP_RECVERR cmsg on listener socket");
+ }
debug("%s error on UDP socket %i: %s",
str_ee_origin(ee), s, strerror_(ee->ee_errno));
@@ -461,15 +580,16 @@ static int udp_sock_recverr(int s)
/**
* udp_sock_errs() - Process errors on a socket
* @c: Execution context
- * @s: Socket to receive from
+ * @ref: epoll reference
* @events: epoll events bitmap
*
* Return: Number of errors handled, or < 0 if we have an unrecoverable error
*/
-int udp_sock_errs(const struct ctx *c, int s, uint32_t events)
+int udp_sock_errs(const struct ctx *c, union epoll_ref ref, uint32_t events)
{
unsigned n_err = 0;
socklen_t errlen;
+ int s = ref.fd;
int rc, err;
ASSERT(!c->no_udp);
@@ -478,7 +598,7 @@ int udp_sock_errs(const struct ctx *c, int s, uint32_t events)
return 0; /* Nothing to do */
/* Empty the error queue */
- while ((rc = udp_sock_recverr(s)) > 0)
+ while ((rc = udp_sock_recverr(c, ref)) > 0)
n_err += rc;
if (rc < 0)
@@ -558,7 +678,7 @@ static void udp_buf_listen_sock_handler(const struct ctx *c,
const socklen_t sasize = sizeof(udp_meta[0].s_in);
int n, i;
- if (udp_sock_errs(c, ref.fd, events) < 0) {
+ if (udp_sock_errs(c, ref, events) < 0) {
err("UDP: Unrecoverable error on listening socket:"
" (%s port %hu)", pif_name(ref.udp.pif), ref.udp.port);
/* FIXME: what now? close/re-open socket? */
@@ -661,7 +781,7 @@ static void udp_buf_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
from_s = uflow->s[ref.flowside.sidei];
- if (udp_sock_errs(c, from_s, events) < 0) {
+ if (udp_sock_errs(c, ref, events) < 0) {
flow_err(uflow, "Unrecoverable error on reply socket");
flow_err_details(uflow);
udp_flow_close(c, uflow);
generated by cgit v1.2.3 (git 2.25.1) at 2025-03-14 12:57:07 +0000