[PATCH v2 bpf-next 16/17] bpf: Change bpf_getsockopt(SOL_IPV6) to reuse do_ipv6_getsockopt()

Martin KaFai Lau
2022-09-02T00:31:56Z

This patch changes bpf_getsockopt(SOL_IPV6) to reuse
do_ipv6_getsockopt(). It removes the duplicated code from
bpf_getsockopt(SOL_IPV6).

This also makes bpf_getsockopt(SOL_IPV6) supporting the same
set of optnames as in bpf_setsockopt(SOL_IPV6). In particular,
this adds IPV6_AUTOFLOWLABEL support to bpf_getsockopt(SOL_IPV6).

ipv6 could be compiled as a module. Like how other code solved it
with stubs in ipv6_stubs.h, this patch adds the do_ipv6_getsockopt
to the ipv6_bpf_stub.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
include/net/ipv6.h | 2 ++
include/net/ipv6_stubs.h | 2 ++
net/core/filter.c | 55 ++++++++++++++++++----------------------
net/ipv6/af_inet6.c | 1 +
net/ipv6/ipv6_sockglue.c | 4 +--
5 files changed, 31 insertions(+), 33 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index a4f24573ed7a..d664ba5812d8 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1160,6 +1160,8 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval
unsigned int optlen);
int ipv6_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
unsigned int optlen);
+int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
+ sockptr_t optval, sockptr_t optlen);
int ipv6_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen);

diff --git a/include/net/ipv6_stubs.h b/include/net/ipv6_stubs.h
index 8692698b01cf..c48186bf4737 100644
--- a/include/net/ipv6_stubs.h
+++ b/include/net/ipv6_stubs.h
@@ -83,6 +83,8 @@ struct ipv6_bpf_stub {
struct sk_buff *skb);
int (*ipv6_setsockopt)(struct sock *sk, int level, int optname,
sockptr_t optval, unsigned int optlen);
+ int (*ipv6_getsockopt)(struct sock *sk, int level, int optname,
+ sockptr_t optval, sockptr_t optlen);
};
extern const struct ipv6_bpf_stub *ipv6_bpf_stub __read_mostly;

diff --git a/net/core/filter.c b/net/core/filter.c
index a9d88fd0541e..b3962c05b5da 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5187,8 +5187,9 @@ static int sol_ip_sockopt(struct sock *sk, int optname,
KERNEL_SOCKPTR(optval), *optlen);
}

-static int sol_ipv6_setsockopt(struct sock *sk, int optname,
- char *optval, int optlen)
+static int sol_ipv6_sockopt(struct sock *sk, int optname,
+ char *optval, int *optlen,
+ bool getopt)
{
if (sk->sk_family != AF_INET6)
return -EINVAL;
@@ -5196,15 +5197,20 @@ static int sol_ipv6_setsockopt(struct sock *sk, int optname,
switch (optname) {
case IPV6_TCLASS:
case IPV6_AUTOFLOWLABEL:
- if (optlen != sizeof(int))
+ if (*optlen != sizeof(int))
return -EINVAL;
break;
default:
return -EINVAL;
}

+ if (getopt)
+ return ipv6_bpf_stub->ipv6_getsockopt(sk, SOL_IPV6, optname,
+ KERNEL_SOCKPTR(optval),
+ KERNEL_SOCKPTR(optlen));
+
return ipv6_bpf_stub->ipv6_setsockopt(sk, SOL_IPV6, optname,
- KERNEL_SOCKPTR(optval), optlen);
+ KERNEL_SOCKPTR(optval), *optlen);
}

static int __bpf_setsockopt(struct sock *sk, int level, int optname,
@@ -5218,7 +5224,7 @@ static int __bpf_setsockopt(struct sock *sk, int level, int optname,
else if (IS_ENABLED(CONFIG_INET) && level == SOL_IP)
return sol_ip_sockopt(sk, optname, optval, &optlen, false);
else if (IS_ENABLED(CONFIG_IPV6) && level == SOL_IPV6)
- return sol_ipv6_setsockopt(sk, optname, optval, optlen);
+ return sol_ipv6_sockopt(sk, optname, optval, &optlen, false);
else if (IS_ENABLED(CONFIG_INET) && level == SOL_TCP)
return sol_tcp_sockopt(sk, optname, optval, &optlen, false);

@@ -5236,43 +5242,30 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
static int __bpf_getsockopt(struct sock *sk, int level, int optname,
char *optval, int optlen)
{
- int err = 0, saved_optlen = optlen;
+ int err, saved_optlen = optlen;

- if (!sk_fullsock(sk))
- goto err_clear;
+ if (!sk_fullsock(sk)) {
+ err = -EINVAL;
+ goto done;
+ }

- if (level == SOL_SOCKET) {
+ if (level == SOL_SOCKET)
err = sol_socket_sockopt(sk, optname, optval, &optlen, true);
- } else if (IS_ENABLED(CONFIG_INET) && level == SOL_TCP) {
+ else if (IS_ENABLED(CONFIG_INET) && level == SOL_TCP)
err = sol_tcp_sockopt(sk, optname, optval, &optlen, true);
- } else if (IS_ENABLED(CONFIG_INET) && level == SOL_IP) {
+ else if (IS_ENABLED(CONFIG_INET) && level == SOL_IP)
err = sol_ip_sockopt(sk, optname, optval, &optlen, true);
- } else if (IS_ENABLED(CONFIG_IPV6) && level == SOL_IPV6) {
- struct ipv6_pinfo *np = inet6_sk(sk);
-
- if (optlen != sizeof(int) || sk->sk_family != AF_INET6)
- goto err_clear;
-
- /* Only some options are supported */
- switch (optname) {
- case IPV6_TCLASS:
- *((int *)optval) = (int)np->tclass;
- break;
- default:
- goto err_clear;
- }
- } else {
- goto err_clear;
- }
+ else if (IS_ENABLED(CONFIG_IPV6) && level == SOL_IPV6)
+ err = sol_ipv6_sockopt(sk, optname, optval, &optlen, true);
+ else
+ err = -EINVAL;

+done:
if (err)
optlen = 0;
if (optlen < saved_optlen)
memset(optval + optlen, 0, saved_optlen - optlen);
return err;
-err_clear:
- memset(optval, 0, optlen);
- return -EINVAL;
}

static int _bpf_getsockopt(struct sock *sk, int level, int optname,
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index cadc97852787..19732b5dce23 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -1058,6 +1058,7 @@ static const struct ipv6_bpf_stub ipv6_bpf_stub_impl = {
.inet6_bind = __inet6_bind,
.udp6_lib_lookup = __udp6_lib_lookup,
.ipv6_setsockopt = do_ipv6_setsockopt,
+ .ipv6_getsockopt = do_ipv6_getsockopt,
};

static int __init inet6_init(void)
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index d9887e3a6077..1193f5a5247d 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1131,8 +1131,8 @@ static int compat_ipv6_get_msfilter(struct sock *sk, sockptr_t optval,
return 0;
}

-static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
- sockptr_t optval, sockptr_t optlen)
+int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
+ sockptr_t optval, sockptr_t optlen)
{
struct ipv6_pinfo *np = inet6_sk(sk);
int len;
--
2.30.2