ipv6: rpl: Remove redundant skb_dst_drop().

RPL code has a pattern where skb_dst_drop() is called before
ip6_route_input().

However, ip6_route_input() calls skb_dst_drop() internally,
so we need not call skb_dst_drop() before ip6_route_input().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230710213511.5364-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6: rpl_iptunnel: Replace 0-length arrays with flexible arrays

Zero-length arrays are deprecated[1]. Replace struct ipv6_rpl_sr_hdr's
"segments" union of 0-length arrays with flexible arrays. Detected with
GCC 13, using -fstrict-flex-arrays=3:

In function 'rpl_validate_srh',
inlined from 'rpl_build_state' at ../net/ipv6/rpl_iptunnel.c:96:7:
../net/ipv6/rpl_iptunnel.c:60:28: warning: array subscript <unknown> is outside array bounds of 'struct in6_addr[0]' [-Warray-bounds=]
60 | if (ipv6_addr_type(&srh->rpl_segaddr[srh->segments_left - 1]) &
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../include/net/rpl.h:12,
from ../net/ipv6/rpl_iptunnel.c:13:
../include/uapi/linux/rpl.h: In function 'rpl_build_state':
../include/uapi/linux/rpl.h:40:33: note: while referencing 'addr'
40 | struct in6_addr addr[0];
| ^~~~

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays

Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230105221533.never.711-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6: rpl_iptunnel: simplify the return expression of rpl_do_srh()

Simplify the return expression.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: rpl*: Fix strange kerneldoc warnings due to bad header

net/ipv6/rpl_iptunnel.c:15: warning: cannot understand function prototype: 'struct rpl_iptunnel_encap '

The header on the file containing the author copyright message uses
kerneldoc /** opener. This confuses the parser when it gets to

struct rpl_iptunnel_encap {
struct ipv6_rpl_sr_hdr srh[0];
};

Similarly:

net//ipv6/rpl.c:10: warning: Function parameter or member 'x' not described in 'IPV6_PFXTAIL_LEN'

where IPV6_PFXTAIL_LEN is a macro definition, not a function.

Convert the header comments to a plain /* comment.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201028013123.931816-1-andrew@lunn.ch
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6: Use struct_size() helper and kcalloc()

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes. Also, remove unnecessary
function ipv6_rpl_srh_alloc_size() and replace kzalloc() with kcalloc(),
which has a 2-factor argument form for multiplication.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: rpl_iptunnel: remove redundant assignments to variable err

The variable err is being initialized with a value that is never
read and it is being updated later with a new value. The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: rpl_iptunnel: Fix potential memory leak in rpl_do_srh_inline

In case memory resources for buf were allocated, release them before
return.

Addresses-Coverity-ID: 1492011 ("Resource leak")
Fixes: a7a29f9c361f ("net: ipv6: add rpl sr tunnel")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: add rpl sr tunnel

This patch adds functionality to configure routes for RPL source routing
functionality. There is no IPIP functionality yet implemented which can
be added later when the cases when to use IPv6 encapuslation comes more
clear.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>