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-rw-r--r--trafgen/Makefile1
-rw-r--r--trafgen_l3.c82
-rw-r--r--trafgen_l3.h25
-rw-r--r--trafgen_proto.c2
4 files changed, 110 insertions, 0 deletions
diff --git a/trafgen/Makefile b/trafgen/Makefile
index 1c95118..4f342ca 100644
--- a/trafgen/Makefile
+++ b/trafgen/Makefile
@@ -21,6 +21,7 @@ trafgen-objs = xmalloc.o \
cpp.o \
trafgen_proto.o \
trafgen_l2.o \
+ trafgen_l3.o \
trafgen_lexer.yy.o \
trafgen_parser.tab.o \
trafgen.o
diff --git a/trafgen_l3.c b/trafgen_l3.c
new file mode 100644
index 0000000..dd45395
--- /dev/null
+++ b/trafgen_l3.c
@@ -0,0 +1,82 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Subject to the GPL, version 2.
+ */
+
+#include <linux/if_ether.h>
+
+#include "csum.h"
+#include "built_in.h"
+#include "trafgen_l2.h"
+#include "trafgen_l3.h"
+#include "trafgen_proto.h"
+#include "trafgen_conf.h"
+
+static struct proto_field ipv4_fields[] = {
+ { .id = IP4_VER, .len = 1, .offset = 0, .shift = 4, .mask = 0xf0 },
+ { .id = IP4_IHL, .len = 1, .offset = 0, .shift = 0, .mask = 0x0f },
+ { .id = IP4_DSCP, .len = 1, .offset = 1, .shift = 2, .mask = 0xfc },
+ { .id = IP4_ECN, .len = 1, .offset = 1, .shift = 0, .mask = 0x03 },
+ { .id = IP4_TOS, .len = 1, .offset = 1 },
+ { .id = IP4_LEN, .len = 2, .offset = 2 },
+ { .id = IP4_ID, .len = 2, .offset = 4 },
+ { .id = IP4_FLAGS, .len = 2, .offset = 6, .shift = 13, .mask = 0xe000 },
+ { .id = IP4_MF, .len = 2, .offset = 6, .shift = 13, .mask = 0x2000 },
+ { .id = IP4_DF, .len = 2, .offset = 6, .shift = 14, .mask = 0x4000 },
+ { .id = IP4_FRAG_OFFS, .len = 2, .offset = 6, .shift = 0, .mask = 0x1fff },
+ { .id = IP4_TTL, .len = 1, .offset = 8 },
+ { .id = IP4_PROTO, .len = 1, .offset = 9 },
+ { .id = IP4_CSUM, .len = 2, .offset = 10 },
+ { .id = IP4_SADDR, .len = 4, .offset = 12 },
+ { .id = IP4_DADDR, .len = 4, .offset = 16 },
+};
+
+static void ipv4_header_init(struct proto_hdr *hdr)
+{
+ struct proto_hdr *lower;
+
+ proto_lower_default_add(PROTO_ETH);
+
+ lower = proto_current_header();
+
+ if (lower->id == PROTO_ETH)
+ proto_field_set_default_be16(lower, ETH_PROTO_ID, ETH_P_IP);
+ else if (lower->id == PROTO_IP4)
+ proto_field_set_default_u8(lower, IP4_PROTO, IPPROTO_IPIP);
+
+ proto_header_fields_add(hdr, ipv4_fields, array_size(ipv4_fields));
+
+ proto_field_set_default_u8(hdr, IP4_VER, 4);
+ proto_field_set_default_u8(hdr, IP4_IHL, 5);
+ proto_field_set_default_dev_ipv4(hdr, IP4_SADDR);
+}
+
+static void ipv4_packet_finish(struct proto_hdr *hdr)
+{
+ struct packet *pkt = current_packet();
+ uint16_t total_len;
+
+ total_len = pkt->len - hdr->pkt_offset;
+ proto_field_set_default_be16(hdr, IP4_LEN, total_len);
+
+ if (!proto_field_is_set(hdr, IP4_CSUM)) {
+ uint16_t csum;
+ uint8_t ihl;
+
+ ihl = proto_field_get_u8(hdr, IP4_IHL);
+ csum = htons(calc_csum(&pkt->payload[hdr->pkt_offset], ihl * 4));
+ proto_field_set_u16(hdr, IP4_CSUM, bswap_16(csum));
+ }
+}
+
+static struct proto_hdr ipv4_hdr = {
+ .id = PROTO_IP4,
+ .layer = PROTO_L3,
+ .header_init = ipv4_header_init,
+ .packet_finish = ipv4_packet_finish,
+};
+
+void protos_l3_init(void)
+{
+ proto_header_register(&ipv4_hdr);
+}
diff --git a/trafgen_l3.h b/trafgen_l3.h
new file mode 100644
index 0000000..9427378
--- /dev/null
+++ b/trafgen_l3.h
@@ -0,0 +1,25 @@
+#ifndef TRAFGEN_L3_H
+#define TRAFGEN_L3_H
+
+enum ip4_field {
+ IP4_VER,
+ IP4_IHL,
+ IP4_DSCP,
+ IP4_ECN,
+ IP4_TOS,
+ IP4_LEN,
+ IP4_ID,
+ IP4_FLAGS,
+ IP4_FRAG_OFFS,
+ IP4_TTL,
+ IP4_PROTO,
+ IP4_CSUM,
+ IP4_SADDR,
+ IP4_DADDR,
+ IP4_DF,
+ IP4_MF,
+};
+
+extern void protos_l3_init(void);
+
+#endif /* TRAFGEN_L2_H */
diff --git a/trafgen_proto.c b/trafgen_proto.c
index 2c090b2..75556f9 100644
--- a/trafgen_proto.c
+++ b/trafgen_proto.c
@@ -12,6 +12,7 @@
#include "xmalloc.h"
#include "trafgen_conf.h"
#include "trafgen_l2.h"
+#include "trafgen_l3.h"
#include "trafgen_proto.h"
#define field_shift_and_mask(f, v) (((v) << (f)->shift) & \
@@ -360,6 +361,7 @@ void protos_init(const char *dev)
ctx.dev = dev;
protos_l2_init();
+ protos_l3_init();
for (p = registered; p; p = p->next)
p->ctx = &ctx;