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pping: Refactor parse_packet_identifer

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Remove the saddr and daddr parmeters from parse_packet_identifier, and
use the is_egress parmeter to perform the saddr/daddr swap inside the
function. Also, minor style fixes.

Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
This commit is contained in:
Simon Sundberg
2021-02-12 11:40:43 +01:00
parent 3268ba87bb
commit 397b44cff7
3 changed files with 29 additions and 19 deletions
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41
pping/pping_helpers.h
View File

@@ -23,8 +23,6 @@
*/
static void map_ipv4_to_ipv6(__be32 ipv4, struct in6_addr *ipv6)
{
/* __u16 ipv4_prefix[6] = {0x0, 0x0, 0x0, 0x0, 0x0, 0xffff}; */
/* __builtin_memcpy(ipv6, ipv4_prefix, sizeof(ipv4_prefix)); */
__builtin_memset(&ipv6->in6_u.u6_addr8[0], 0x00, 10);
__builtin_memset(&ipv6->in6_u.u6_addr8[10], 0xff, 2);
ipv6->in6_u.u6_addr32[3] = ipv4;
@@ -87,6 +85,7 @@ static int parse_tcp_ts(struct tcphdr *tcph, void *data_end, __u32 *tsval,
* and dest, respectively, and 0 will be returned. On failure, -1 will be
* returned.
*/
// Has 6 parameters (one too many)
static int parse_tcp_identifier(struct hdr_cursor *nh, void *data_end,
bool is_egress, struct flow_address *saddr,
struct flow_address *daddr, __u32 *identifier)
@@ -96,6 +95,7 @@ static int parse_tcp_identifier(struct hdr_cursor *nh, void *data_end,
if (parse_tcphdr(nh, data_end, &tcph) < 0)
return -1;
if (parse_tcp_ts(tcph, data_end, &tsval, &tsecr) < 0)
return -1; //Possible TODO, fall back on seq/ack instead
@@ -108,20 +108,32 @@ static int parse_tcp_identifier(struct hdr_cursor *nh, void *data_end,
/*
* Attempts to parse the packet limited by the data and data_end pointers,
* to retrieve a protocol dependent packet identifier. If sucessful, the
* ipv and identifier of p_id will be set, saddr and daddr (which may be part
* of p_id) will be filled with the source and destionation addresses of the
* pointed to p_id will be filled with parsed information from the packet
* packet, and 0 will be returned. On failure, -1 will be returned.
* If is_egress saddr and daddr will match source and destination of packet,
* respectively, and identifier will be set to the identifer for an outgoing
* packet. Otherwise, saddr and daddr will be swapped (will match
* destination and source of packet, respectively), and identifier will be
* set to the identifier of a response.
*/
static int parse_packet_identifier(void *data, void *data_end, bool is_egress,
struct packet_id *p_id,
struct flow_address *saddr,
struct flow_address *daddr)
struct packet_id *p_id)
{
int proto, err;
struct hdr_cursor nh = { .pos = data };
struct ethhdr *eth;
struct iphdr *iph;
struct ipv6hdr *ip6h;
int proto, err;
struct flow_address *saddr, *daddr;
// Switch saddr <--> daddr on ingress to match egress
if (is_egress) {
saddr = &p_id->flow.saddr;
daddr = &p_id->flow.daddr;
} else {
saddr = &p_id->flow.daddr;
daddr = &p_id->flow.saddr;
}
proto = parse_ethhdr(&nh, data_end, &eth);
@@ -132,18 +144,19 @@ static int parse_packet_identifier(void *data, void *data_end, bool is_egress,
} else if (proto == bpf_htons(ETH_P_IPV6)) {
p_id->flow.ipv = AF_INET6;
proto = parse_ip6hdr(&nh, data_end, &ip6h);
} else
} else {
return -1;
}
// Add new protocols here
if (proto == IPPROTO_TCP)
if (proto == IPPROTO_TCP) {
err = parse_tcp_identifier(&nh, data_end, is_egress, saddr,
daddr, &p_id->identifier);
else
return -1;
if (err)
if (err)
return -1;
} else {
return -1;
}
// Sucessfully parsed packet identifier - fill in IP-addresses and return
if (p_id->flow.ipv == AF_INET) {

3
pping/pping_kern_tc.c
View File

@@ -37,8 +37,7 @@ int tc_bpf_prog_egress(struct __sk_buff *skb)
void *data = (void *)(long)skb->data;
void *data_end = (void *)(long)skb->data_end;
if (parse_packet_identifier(data, data_end, true, &p_id,
&p_id.flow.saddr, &p_id.flow.daddr) < 0)
if (parse_packet_identifier(data, data_end, true, &p_id) < 0)
goto end;
p_ts.timestamp = bpf_ktime_get_ns(); // or bpf_ktime_get_boot_ns

4
pping/pping_kern_xdp.c
View File

@@ -32,9 +32,7 @@ int xdp_prog_ingress(struct xdp_md *ctx)
void *data = (void *)(long)ctx->data;
void *data_end = (void *)(long)ctx->data_end;
// saddr and daddr in reverse order of egress (source <--> dest)
if (parse_packet_identifier(data, data_end, false, &p_id,
&p_id.flow.daddr, &p_id.flow.saddr) < 0)
if (parse_packet_identifier(data, data_end, false, &p_id) < 0)
goto end;
p_ts = bpf_map_lookup_elem(&ts_start, &p_id);