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-rw-r--r--tap.c2
-rw-r--r--tap.h2
-rw-r--r--udp.c87
-rw-r--r--udp_internal.h2
-rw-r--r--udp_vu.c4
5 files changed, 81 insertions, 16 deletions
diff --git a/tap.c b/tap.c
index 6f7063e..57d0795 100644
--- a/tap.c
+++ b/tap.c
@@ -159,7 +159,7 @@ void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
ip4h->saddr = src.s_addr;
ip4h->daddr = dst.s_addr;
ip4h->check = csum_ip4_header(l3len, proto, src, dst);
- return ip4h + 1;
+ return (char *)ip4h + sizeof(*ip4h);
}
/**
diff --git a/tap.h b/tap.h
index a2cf9bc..9ac17ce 100644
--- a/tap.h
+++ b/tap.h
@@ -50,6 +50,8 @@ void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
void *tap_push_uh4(struct udphdr *uh, struct in_addr src, in_port_t sport,
struct in_addr dst, in_port_t dport,
const void *in, size_t dlen);
+void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
+ struct in_addr dst, size_t l4len, uint8_t proto);
void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
struct in_addr dst, in_port_t dport,
const void *in, size_t dlen);
diff --git a/udp.c b/udp.c
index 923cc38..b72c3ce 100644
--- a/udp.c
+++ b/udp.c
@@ -87,6 +87,7 @@
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
+#include <netinet/ip_icmp.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
@@ -112,6 +113,9 @@
#include "udp_internal.h"
#include "udp_vu.h"
+/* Maximum UDP data to be returned in ICMP messages */
+#define ICMP4_MAX_DLEN 8
+
/* "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 +407,75 @@ 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_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[ICMP4_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 +505,15 @@ static int udp_sock_recverr(int s)
}
ee = (const struct sock_extended_err *)CMSG_DATA(hdr);
+ if (ref.type == EPOLL_TYPE_UDP_REPLY) {
+ flow_sidx_t sidx = flow_sidx_opposite(ref.flowside);
+ const struct flowside *toside = flowside_at_sidx(sidx);
- /* TODO: When possible propagate and otherwise handle errors */
+ udp_send_conn_fail_icmp4(c, ee, toside, saddr.sa4.sin_addr,
+ data, rc);
+ } 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 +523,16 @@ 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 +541,7 @@ 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 +621,7 @@ 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 +724,7 @@ 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);
diff --git a/udp_internal.h b/udp_internal.h
index cc80e30..3b081f5 100644
--- a/udp_internal.h
+++ b/udp_internal.h
@@ -30,5 +30,5 @@ size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
const struct flowside *toside, size_t dlen,
bool no_udp_csum);
-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);
#endif /* UDP_INTERNAL_H */
diff --git a/udp_vu.c b/udp_vu.c
index 4123510..c26a223 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -227,7 +227,7 @@ void udp_vu_listen_sock_handler(const struct ctx *c, union epoll_ref ref,
struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE];
int 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);
return;
@@ -302,7 +302,7 @@ void udp_vu_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
ASSERT(!c->no_udp);
- 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 2025-03-12 14:09:01 +0000