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udhcpc: fix BPF filter. Hopefully fixes the root cause of 4598 and 6746

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Use a *signed* large positive value in BPF filter to indicate success.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2014-02-19 14:17:11 +01:00
parent 50e4cc29f5
commit ffc3a93d0d
2 changed files with 5 additions and 4 deletions
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2
networking/udhcp/d6_dhcpc.c
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@ -711,7 +711,7 @@ static int d6_raw_socket(int ifindex)
/* jump to L3 if udp dport is CLIENT_PORT6, else to L4 */
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
/* L3: accept packet */
BPF_STMT(BPF_RET|BPF_K, 0xffffffff),
BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
/* L4: discard packet */
BPF_STMT(BPF_RET|BPF_K, 0),
};

7
networking/udhcp/dhcpc.c
View File

@ -1025,9 +1025,10 @@ static int udhcp_raw_socket(int ifindex)
BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
/* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
/* L3: accept packet */
BPF_STMT(BPF_RET|BPF_K, 0xffffffff),
/* L4: discard packet */
/* L3: accept packet ("accept 0x7fffffff bytes") */
/* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
/* L4: discard packet ("accept zero bytes") */
BPF_STMT(BPF_RET|BPF_K, 0),
};
static const struct sock_fprog filter_prog = {