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| author | David Herrmann <dh.herrmann@gmail.com> | 2015-06-17 17:14:33 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-06-21 19:18:18 +0200 |
| commit | b42be38b2778eda2237fc759e55e3b698b05b315 (patch) | |
| tree | 52e997d4f7487cc1f09f503bb22df0a132d9dc1a /net/netlink | |
| parent | sock_diag: fetch source port from inet_sock (diff) | |
| download | linux-b42be38b2778eda2237fc759e55e3b698b05b315.tar.xz linux-b42be38b2778eda2237fc759e55e3b698b05b315.zip | |
netlink: add API to retrieve all group memberships
This patch adds getsockopt(SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS) to
retrieve all groups a socket is a member of. Currently, we have to use
getsockname() and look at the nl.nl_groups bitmask. However, this mask is
limited to 32 groups. Hence, similar to NETLINK_ADD_MEMBERSHIP and
NETLINK_DROP_MEMBERSHIP, this adds a separate sockopt to manager higher
groups IDs than 32.
This new NETLINK_LIST_MEMBERSHIPS option takes a pointer to __u32 and the
size of the array. The array is filled with the full membership-set of the
socket, and the required array size is returned in optlen. Hence,
user-space can retry with a properly sized array in case it was too small.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/af_netlink.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 69d67c300b80..dea925388a5b 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2290,6 +2290,28 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname, return -EFAULT; err = 0; break; + case NETLINK_LIST_MEMBERSHIPS: { + int pos, idx, shift; + + err = 0; + netlink_table_grab(); + for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { + if (len - pos < sizeof(u32)) + break; + + idx = pos / sizeof(unsigned long); + shift = (pos % sizeof(unsigned long)) * 8; + if (put_user((u32)(nlk->groups[idx] >> shift), + (u32 __user *)(optval + pos))) { + err = -EFAULT; + break; + } + } + if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen)) + err = -EFAULT; + netlink_table_ungrab(); + break; + } default: err = -ENOPROTOOPT; } |