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udhcp6: fix releasing

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Patch is based on work by tiggerswelt.net. They say:
"
We wanted udhcpc6 to release its IPv6-Addresses on
quit (-R-commandline-option) which turned out to generate once again
kind of garbage on the network-link.
We tracked this down to two issues:

 - udhcpc6 uses a variable called "srv6_buf" to send packets to
   the dhcp6-server, but this variable is never initialized correctly
   and contained kind of a garbage-address

 - The address of the dhcp6-server is usually a link-local-address,
   that requires an interface-index when using connect() on an AF_INET6-
   socket

We added an
additional parameter for ifindex to d6_send_kernel_packet() and made
d6_recv_raw_packet() to capture the address of the dhcp6-server and
forward it to its callee.
"

Three last patches together:

function                                             old     new   delta
d6_read_interface                                      -     454    +454
d6_recv_raw_packet                                     -     283    +283
option_to_env                                        249     504    +255
.rodata                                           165226  165371    +145
send_d6_discover                                     195     237     +42
send_d6_select                                       118     159     +41
send_d6_renew                                        173     186     +13
send_d6_release                                      162     173     +11
opt_req                                                -      10     +10
d6_send_kernel_packet                                304     312      +8
opt_fqdn_req                                           -       6      +6
d6_mcast_from_client_config_ifindex                   48      51      +3
d6_find_option                                        63      61      -2
udhcpc6_main                                        2416    2411      -5
static.d6_recv_raw_packet                            266       -    -266
------------------------------------------------------------------------------
(add/remove: 5/1 grow/shrink: 8/2 up/down: 1271/-273)         Total: 998 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2017-03-27 22:32:44 +02:00
parent 64d58aa806
commit ed898ed2dd
3 changed files with 13 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
networking/udhcp/d6_packet.c
View File

@@ -127,7 +127,8 @@ int FAST_FUNC d6_send_raw_packet(
int FAST_FUNC d6_send_kernel_packet(
struct d6_packet *d6_pkt, unsigned d6_pkt_size,
struct in6_addr *src_ipv6, int source_port,
struct in6_addr *dst_ipv6, int dest_port)
struct in6_addr *dst_ipv6, int dest_port,
int ifindex)
{
struct sockaddr_in6 sa;
int fd;
@@ -154,6 +155,7 @@ int FAST_FUNC d6_send_kernel_packet(
sa.sin6_family = AF_INET6;
sa.sin6_port = htons(dest_port);
sa.sin6_addr = *dst_ipv6; /* struct copy */
sa.sin6_scope_id = ifindex;
if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
msg = "connect";
goto ret_close;