| Daniele Moro | 8088956 | 2021-09-08 10:09:26 +0200 | [diff] [blame^] | 1 | from scapy.contrib.gtp import GTP_U_Header, GTPPDUSessionContainer |
| 2 | from scapy.layers.inet import IP, UDP |
| 3 | from scapy.layers.l2 import Ether |
| 4 | import codecs |
| 5 | |
| 6 | UDP_GTP_PORT = 2152 |
| 7 | DEFAULT_GTP_TUNNEL_SPORT = 1234 # arbitrary, but different from 2152 |
| 8 | |
| 9 | IP_HDR_BYTES = 20 |
| 10 | UDP_HDR_BYTES = 8 |
| 11 | GTPU_HDR_BYTES = 8 |
| 12 | GTPU_OPTIONS_HDR_BYTES = 4 |
| 13 | GTPU_EXT_PSC_BYTES = 4 |
| 14 | |
| 15 | |
| 16 | def simple_gtp_udp_packet( |
| 17 | eth_dst=None, |
| 18 | eth_src=None, |
| 19 | ip_src="192.168.0.1", |
| 20 | ip_dst="192.168.0.2", |
| 21 | s1u_addr="100.0.0.1", |
| 22 | enb_addr="192.168.101.1", |
| 23 | ip_ttl=64, |
| 24 | gtp_teid=0xFF, # dummy teid |
| 25 | pktlen=136, |
| 26 | ext_psc_type=None, |
| 27 | ext_psc_qfi=0, |
| 28 | ): |
| 29 | pktlen = pktlen - IP_HDR_BYTES - UDP_HDR_BYTES - GTPU_HDR_BYTES |
| 30 | if ext_psc_type is not None: |
| 31 | pktlen = pktlen - GTPU_OPTIONS_HDR_BYTES - GTPU_EXT_PSC_BYTES |
| 32 | pkt = simple_udp_packet(eth_src=eth_src, eth_dst=eth_dst, ip_src=ip_src, |
| 33 | ip_dst=ip_dst, pktlen=pktlen) |
| 34 | gtp_pkt = pkt_add_gtp( |
| 35 | pkt, |
| 36 | out_ipv4_src=enb_addr, |
| 37 | out_ipv4_dst=s1u_addr, |
| 38 | teid=gtp_teid, |
| 39 | ext_psc_type=ext_psc_type, |
| 40 | ext_psc_qfi=ext_psc_qfi, |
| 41 | ) |
| 42 | gtp_pkt[Ether].src = eth_src |
| 43 | gtp_pkt[Ether].dst = eth_dst |
| 44 | gtp_pkt[IP].ttl = ip_ttl |
| 45 | return gtp_pkt |
| 46 | |
| 47 | |
| 48 | def pkt_add_gtp( |
| 49 | pkt, |
| 50 | out_ipv4_src, |
| 51 | out_ipv4_dst, |
| 52 | teid, |
| 53 | sport=DEFAULT_GTP_TUNNEL_SPORT, |
| 54 | dport=UDP_GTP_PORT, |
| 55 | ext_psc_type=None, |
| 56 | ext_psc_qfi=None, |
| 57 | ): |
| 58 | gtp_pkt = ( |
| 59 | Ether(src=pkt[Ether].src, dst=pkt[Ether].dst) |
| 60 | / IP(src=out_ipv4_src, dst=out_ipv4_dst, tos=0, id=0x1513, flags=0, |
| 61 | frag=0, ) |
| 62 | / UDP(sport=sport, dport=dport, chksum=0) |
| 63 | / GTP_U_Header(gtp_type=255, teid=teid) |
| 64 | ) |
| 65 | if ext_psc_type is not None: |
| 66 | # Add QoS Flow Identifier (QFI) as an extension header (required for 5G RAN) |
| 67 | gtp_pkt = gtp_pkt / GTPPDUSessionContainer(type=ext_psc_type, |
| 68 | QFI=ext_psc_qfi) |
| 69 | return gtp_pkt / pkt[Ether].payload |
| 70 | |
| 71 | |
| 72 | # Simplified version of simple_udp_packet from https://github.com/p4lang/ptf/blob/master/src/ptf/testutils.py |
| 73 | def simple_udp_packet( |
| 74 | pktlen=100, |
| 75 | eth_dst="00:01:02:03:04:05", |
| 76 | eth_src="00:06:07:08:09:0a", |
| 77 | ip_src="192.168.0.1", |
| 78 | ip_dst="192.168.0.2", |
| 79 | udp_sport=1234, |
| 80 | udp_dport=80, |
| 81 | udp_payload=None, |
| 82 | ): |
| 83 | pkt = Ether(src=eth_src, dst=eth_dst) / IP(src=ip_src, dst=ip_dst) / UDP( |
| 84 | sport=udp_sport, dport=udp_dport) |
| 85 | if udp_payload: |
| 86 | pkt = pkt / udp_payload |
| 87 | return pkt / codecs.decode( |
| 88 | "".join(["%02x" % (x % 256) for x in range(pktlen - len(pkt))]), "hex") |