Issue while decoding fragmentation flags in IP packet decoding

[YannGarcia]

Hello,

The issue is located in src/c/packet_ip.c lines 50 to 52 where fragmentation flags (Don't fragment and More fragment flags) are not processed properly.
A call to C ntohs() function shall be used:

• (jboolean)(((ntohs(ip_pkt->ip_off)&IP_RF)>0)?JNI_TRUE:JNI_FALSE),
• (jboolean)((((ntohs(ip_pkt->ip_off)) &IP_DF)>0)?JNI_TRUE:JNI_FALSE),
• (jboolean)(((ntohs(ip_pkt->ip_off) &IP_MF)>0)?JNI_TRUE:JNI_FALSE),

This fixed was tested on both Win10 & Linux Ubuntu 18.04 TLS

In addition, I also replace line 44:

• (jbyte)ip_pkt->ip_v