Add nl_addr_get_all() to read all addresses from the template interface
into c->addrs[] array, rather than just selecting the "best" one.
This allows multi-address configurations where the template interface
has multiple IPv4 or IPv6 addresses assigned to it, all of which
will now be copied to the guest namespace when using --config-net.
For IPv6, the function also captures the link-local address into
c->ip6.our_tap_ll as a side effect.
Update conf_ip4() and conf_ip6() to use nl_addr_get_all() when no
user-specified addresses are present.
Signed-off-by: Jon Maloy
Reviewed-by: David Gibson
---
v7: -Excluded all link local addresses from host to be added to array
-Minor comment change suggested by Stefano
---
conf.c | 51 ++++++++++++++++++++++++++-------------------------
netlink.c | 53 +++++++++++++++++++++++++++++------------------------
netlink.h | 3 +--
3 files changed, 56 insertions(+), 51 deletions(-)
diff --git a/conf.c b/conf.c
index 8b4a7a0..924ade2 100644
--- a/conf.c
+++ b/conf.c
@@ -736,6 +736,7 @@ static int conf_ip4_prefix(const char *arg)
static unsigned int conf_ip4(struct ctx *c, unsigned int ifi)
{
struct ip4_ctx *ip4 = &c->ip4;
+ const struct guest_addr *a;
if (!ifi)
ifi = nl_get_ext_if(nl_sock, AF_INET);
@@ -755,24 +756,24 @@ static unsigned int conf_ip4(struct ctx *c, unsigned int ifi)
}
}
- if (!fwd_get_addr(c, AF_INET, 0, 0)) {
- struct in_addr addr;
- int prefix_len;
- int rc = nl_addr_get(nl_sock, ifi, AF_INET,
- &addr, &prefix_len, NULL);
+ a = fwd_get_addr(c, AF_INET, CONF_ADDR_USER, 0);
+ if (!a) {
+ int rc = nl_addr_get_all(c, nl_sock, ifi, AF_INET);
+
if (rc < 0) {
- debug("Couldn't discover IPv4 address: %s",
+ debug("Couldn't discover IPv4 addresses: %s",
strerror_(-rc));
return 0;
}
- if (IN4_IS_ADDR_UNSPECIFIED(&addr))
+ if (!rc || !fwd_get_addr(c, AF_INET, 0, 0))
return 0;
- fwd_set_addr(c, &inany_from_v4(addr), CONF_ADDR_HOST,
- prefix_len);
- ip4->addr_seen = addr;
+ a = fwd_get_addr(c, AF_INET, CONF_ADDR_HOST, 0);
}
+ if (a)
+ ip4->addr_seen = *inany_v4(&a->addr);
+
ip4->our_tap_addr = ip4->guest_gw;
return ifi;
@@ -805,8 +806,6 @@ static unsigned int conf_ip6(struct ctx *c, unsigned int ifi)
{
struct ip6_ctx *ip6 = &c->ip6;
const struct guest_addr *a;
- union inany_addr addr;
- int prefix_len = 0;
int rc;
if (!ifi)
@@ -826,24 +825,26 @@ static unsigned int conf_ip6(struct ctx *c, unsigned int ifi)
}
}
- rc = nl_addr_get(nl_sock, ifi, AF_INET6, &addr.a6,
- &prefix_len, &ip6->our_tap_ll);
- if (rc < 0) {
- debug("Couldn't discover IPv6 address: %s", strerror_(-rc));
- return 0;
- }
-
- a = fwd_get_addr(c, AF_INET6, 0, 0);
+ a = fwd_get_addr(c, AF_INET6, CONF_ADDR_USER, 0);
if (!a) {
- if (IN6_IS_ADDR_UNSPECIFIED(&addr))
+ rc = nl_addr_get_all(c, nl_sock, ifi, AF_INET6);
+ if (rc < 0) {
+ debug("Couldn't discover IPv6 addresses: %s",
+ strerror_(-rc));
return 0;
-
- fwd_set_addr(c, &addr, CONF_ADDR_HOST, prefix_len);
- ip6->addr_seen = addr.a6;
+ }
+ a = fwd_get_addr(c, AF_INET6, CONF_ADDR_HOST, 0);
} else {
- ip6->addr_seen = a->addr.a6;
+ rc = nl_addr_get_ll(nl_sock, ifi, &ip6->our_tap_ll);
+ if (rc < 0) {
+ debug("Couldn't get link-local address: %s",
+ strerror_(-rc));
+ }
}
+ if (a)
+ ip6->addr_seen = a->addr.a6;
+
if (IN6_IS_ADDR_LINKLOCAL(&ip6->guest_gw))
ip6->our_tap_ll = ip6->guest_gw;
diff --git a/netlink.c b/netlink.c
index e07b47f..3f5a812 100644
--- a/netlink.c
+++ b/netlink.c
@@ -747,20 +747,20 @@ int nl_addr_set_ll_nodad(int s, unsigned int ifi)
}
/**
- * nl_addr_get() - Get most specific global address, given interface and family
+ * nl_addr_get_all() - Get all addresses for a given interface into ctx
+ * @c: Execution context
* @s: Netlink socket
- * @ifi: Interface index in outer network namespace
- * @af: Address family
- * @addr: Global address to fill
- * @prefix_len: Mask or prefix length, to fill
- * @addr_l: Link-scoped address to fill (for IPv6)
+ * @ifi: Interface index
+ * @af: Address family (AF_INET or AF_INET6)
*
- * Return: 0 on success, negative error code on failure
+ * Populates c->addrs[] with all non-deprecated addresses from the interface.
+ * For IPv6, also captures link-local address in c->ip6.our_tap_ll.
+ * Skips IPv6 link-local addresses for the main array.
+ *
+ * Return: number of addresses added, or negative error code on failure
*/
-int nl_addr_get(int s, unsigned int ifi, sa_family_t af,
- void *addr, int *prefix_len, void *addr_l)
+int nl_addr_get_all(struct ctx *c, int s, unsigned int ifi, sa_family_t af)
{
- uint8_t prefix_max = 0, prefix_max_ll = 0;
struct req_t {
struct nlmsghdr nlh;
struct ifaddrmsg ifa;
@@ -771,6 +771,7 @@ int nl_addr_get(int s, unsigned int ifi, sa_family_t af,
struct nlmsghdr *nh;
char buf[NLBUFSIZ];
ssize_t status;
+ int count = 0;
uint32_t seq;
seq = nl_send(s, &req, RTM_GETADDR, NLM_F_DUMP, sizeof(req));
@@ -784,27 +785,31 @@ int nl_addr_get(int s, unsigned int ifi, sa_family_t af,
for (rta = IFA_RTA(ifa), na = IFA_PAYLOAD(nh); RTA_OK(rta, na);
rta = RTA_NEXT(rta, na)) {
- if ((af == AF_INET && rta->rta_type != IFA_LOCAL) ||
- (af == AF_INET6 && rta->rta_type != IFA_ADDRESS))
- continue;
+ union inany_addr addr;
- if (ifa->ifa_prefixlen > prefix_max && addr &&
- (af == AF_INET || ifa->ifa_scope < RT_SCOPE_LINK)) {
- memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
+ if (af == AF_INET && rta->rta_type != IFA_LOCAL)
+ continue;
+ if (af == AF_INET6 && rta->rta_type != IFA_ADDRESS)
+ continue;
- prefix_max = *prefix_len = ifa->ifa_prefixlen;
+ /* Skip link-local addresses (kernel auto-configures) */
+ if (ifa->ifa_scope == RT_SCOPE_LINK) {
+ if (af == AF_INET)
+ continue;
+ memcpy(&c->ip6.our_tap_ll, RTA_DATA(rta),
+ sizeof(c->ip6.our_tap_ll));
+ continue;
}
- if (addr_l &&
- af == AF_INET6 && ifa->ifa_scope == RT_SCOPE_LINK &&
- ifa->ifa_prefixlen > prefix_max_ll) {
- memcpy(addr_l, RTA_DATA(rta), RTA_PAYLOAD(rta));
+ inany_from_af(&addr, af, RTA_DATA(rta));
+ fwd_set_addr(c, &addr, CONF_ADDR_HOST,
+ ifa->ifa_prefixlen);
- prefix_max_ll = ifa->ifa_prefixlen;
- }
+ count++;
}
}
- return status;
+
+ return status < 0 ? status : count;
}
/**
diff --git a/netlink.h b/netlink.h
index b22f485..3af6d58 100644
--- a/netlink.h
+++ b/netlink.h
@@ -19,8 +19,7 @@ int nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw);
int nl_route_set_def(int s, unsigned int ifi, sa_family_t af, const void *gw);
int nl_route_dup(int s_src, unsigned int ifi_src,
int s_dst, unsigned int ifi_dst, sa_family_t af);
-int nl_addr_get(int s, unsigned int ifi, sa_family_t af,
- void *addr, int *prefix_len, void *addr_l);
+int nl_addr_get_all(struct ctx *c, int s, unsigned int ifi, sa_family_t af);
bool nl_neigh_mac_get(int s, const union inany_addr *addr, int ifi,
unsigned char *mac);
int nl_addr_set(int s, unsigned int ifi, sa_family_t af,
--
2.52.0