From 17600d6d6ef0edf60bbf64c5bef594a8a07547cc Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Tue, 19 Oct 2021 09:01:27 +0200
Subject: netlink, conf: Actually get prefix/mask length
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
conf.c | 10 ++++++++--
netlink.c | 13 ++++++++-----
netlink.h | 2 +-
pasta.c | 9 +++++++--
4 files changed, 24 insertions(+), 10 deletions(-)
diff --git a/conf.c b/conf.c
index 4287630..8e96368 100644
--- a/conf.c
+++ b/conf.c
@@ -469,7 +469,11 @@ static void conf_ip(struct ctx *c)
nl_route(0, c->ifi, AF_INET, &c->gw4);
if (!c->addr4) {
- nl_addr(0, c->ifi, AF_INET, &c->addr4, 0, NULL);
+ int mask_len = 0;
+
+ nl_addr(0, c->ifi, AF_INET, &c->addr4, &mask_len, NULL);
+ c->mask4 = htonl(0xffffffff << (32 - mask_len));
+
if (!c->mask4) {
if (IN_CLASSA(ntohl(c->addr4)))
c->mask4 = htonl(IN_CLASSA_NET);
@@ -492,12 +496,14 @@ static void conf_ip(struct ctx *c)
memset(&c->mac_guest, 0xff, sizeof(c->mac_guest));
if (v6 != IP_VERSION_DISABLED) {
+ int prefix_len = 0;
+
if (IN6_IS_ADDR_UNSPECIFIED(&c->gw6))
nl_route(0, c->ifi, AF_INET6, &c->gw6);
nl_addr(0, c->ifi, AF_INET6,
IN6_IS_ADDR_UNSPECIFIED(&c->addr6) ? &c->addr6 : NULL,
- 0, &c->addr6_ll);
+ &prefix_len, &c->addr6_ll);
memcpy(&c->addr6_seen, &c->addr6, sizeof(c->addr4_seen));
memcpy(&c->addr6_ll_seen, &c->addr6, sizeof(c->addr4_seen));
diff --git a/netlink.c b/netlink.c
index 4faa697..10d8a92 100644
--- a/netlink.c
+++ b/netlink.c
@@ -346,10 +346,11 @@ next:
* @ifi: Interface index
* @af: Address family
* @addr: Global address to fill if zero, to set if not, ignored if NULL
+ * @prefix_len: Mask or prefix length, set or fetched (for IPv4)
* @addr_l: Link-scoped address to fill, NULL if not requested
*/
void nl_addr(int ns, unsigned int ifi, sa_family_t af,
- void *addr, int prefix_len, void *addr_l)
+ void *addr, int *prefix_len, void *addr_l)
{
int set = addr && ((af == AF_INET6 && !IN6_IS_ADDR_UNSPECIFIED(addr)) ||
(af == AF_INET && *(uint32_t *)addr));
@@ -380,7 +381,7 @@ void nl_addr(int ns, unsigned int ifi, sa_family_t af,
.ifa.ifa_family = af,
.ifa.ifa_index = ifi,
- .ifa.ifa_prefixlen = prefix_len,
+ .ifa.ifa_prefixlen = *prefix_len,
};
struct ifaddrmsg *ifa;
struct nlmsghdr *nh;
@@ -430,12 +431,14 @@ void nl_addr(int ns, unsigned int ifi, sa_family_t af,
if (rta->rta_type != IFA_ADDRESS)
continue;
- if (af == AF_INET && addr && !*(uint32_t *)addr)
+ if (af == AF_INET && addr && !*(uint32_t *)addr) {
memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
- else if (af == AF_INET6 && addr &&
+ *prefix_len = ifa->ifa_prefixlen;
+ } else if (af == AF_INET6 && addr &&
ifa->ifa_scope == RT_SCOPE_UNIVERSE &&
- IN6_IS_ADDR_UNSPECIFIED(addr))
+ IN6_IS_ADDR_UNSPECIFIED(addr)) {
memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
+ }
if (addr_l &&
af == AF_INET6 && ifa->ifa_scope == RT_SCOPE_LINK &&
diff --git a/netlink.h b/netlink.h
index 460c2f1..840e451 100644
--- a/netlink.h
+++ b/netlink.h
@@ -2,5 +2,5 @@ int nl_sock_init(struct ctx *c);
unsigned int nl_get_ext_if(int *v4, int *v6);
void nl_route(int ns, unsigned int ifi, sa_family_t af, void *gw);
void nl_addr(int ns, unsigned int ifi, sa_family_t af,
- void *addr, int prefix_len, void *addr_l);
+ void *addr, int *prefix_len, void *addr_l);
void nl_link(int ns, unsigned int ifi, void *mac, int up, int mtu);
diff --git a/pasta.c b/pasta.c
index b609e36..fe0bf0e 100644
--- a/pasta.c
+++ b/pasta.c
@@ -233,16 +233,21 @@ void pasta_ns_conf(struct ctx *c)
nl_link(1, 1 /* lo */, MAC_ZERO, 1, 0);
if (c->pasta_conf_ns) {
+ int prefix_len;
+
nl_link(1, c->pasta_ifi, c->mac_guest, 1, c->mtu);
if (c->v4) {
+ prefix_len = __builtin_popcount(c->mask4);
nl_addr(1, c->pasta_ifi, AF_INET, &c->addr4,
- __builtin_popcount(c->mask4), NULL);
+ &prefix_len, NULL);
nl_route(1, c->pasta_ifi, AF_INET, &c->gw4);
}
if (c->v6) {
- nl_addr(1, c->pasta_ifi, AF_INET6, &c->addr6, 64, NULL);
+ prefix_len = 64;
+ nl_addr(1, c->pasta_ifi, AF_INET6, &c->addr6,
+ &prefix_len, NULL);
nl_route(1, c->pasta_ifi, AF_INET6, &c->gw6);
}
} else {
--
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