From cf3c9ef8b5255033e9527541c3dc61fc491670f1 Mon Sep 17 00:00:00 2001
From: David Timber <mieabby@gmail.com>
Date: Mon, 14 Sep 2020 16:55:15 +0930
Subject: * recon: determine source address
---
src/recon.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 54 insertions(+), 2 deletions(-)
(limited to 'src')
diff --git a/src/recon.c b/src/recon.c
index 94b1a2e..bd09b09 100644
--- a/src/recon.c
+++ b/src/recon.c
@@ -61,6 +61,8 @@ struct prne_recon {
prne_llist_entry_t *ii_ptr;
size_t t_ptr;
int fd[RCN_NB_FD][2];
+ uint8_t v6_saddr[16];
+ uint8_t v4_saddr[4];
uint32_t seq_mask;
uint16_t s_port;
bool loop;
@@ -235,6 +237,54 @@ static prne_ipv_t rcn_main_genaddr_ii (
return ret;
}
+static void rcn_main_update_saddr (prne_recon_t *ctx) {
+ int fd;
+ socklen_t sl;
+
+ fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (fd >= 0) {
+ static const uint8_t TEST_ADDR[4] = { 192, 0, 2, 1 };
+ struct sockaddr_in sa;
+
+ prne_memzero(&sa, sizeof(sa));
+ sa.sin_family = AF_INET;
+ sa.sin_port = 1024;
+ memcpy(&sa.sin_addr, TEST_ADDR, 4);
+
+ sl = sizeof(sa);
+ if (connect(fd, (struct sockaddr*)&sa, sl) == 0 &&
+ getsockname(fd, (struct sockaddr*)&sa, &sl) == 0 &&
+ sl >= sizeof(sa))
+ {
+ memcpy(ctx->v4_saddr, &sa.sin_addr, 4);
+ }
+ prne_close(fd);
+ }
+
+ fd = socket(AF_INET6, SOCK_DGRAM, 0);
+ if (fd >= 0) {
+ static const uint8_t TEST_ADDR[16] = {
+ 0x20, 0x01, 0x0d, 0xb8, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01
+ };
+ struct sockaddr_in6 sa;
+
+ prne_memzero(&sa, sizeof(sa));
+ sa.sin6_family = AF_INET6;
+ sa.sin6_port = 1024;
+ memcpy(&sa.sin6_addr, TEST_ADDR, 16);
+
+ sl = sizeof(sa);
+ if (connect(fd, (struct sockaddr*)&sa, sl) == 0 &&
+ getsockname(fd, (struct sockaddr*)&sa, &sl) == 0 &&
+ sl >= sizeof(sa))
+ {
+ memcpy(ctx->v6_saddr, &sa.sin6_addr, 16);
+ }
+ prne_close(fd);
+ }
+}
+
static prne_ipv_t rcn_main_genaddr_param (
prne_recon_t *ctx,
uint8_t *src,
@@ -255,7 +305,7 @@ static prne_ipv_t rcn_main_genaddr_param (
prne_bitop_inv(net->mask, src, 4); // use src as host mask
prne_bitop_and(src, dst, dst, 4); // extract host
prne_bitop_or(net->addr.addr, dst, dst, 4); // combine with network
- prne_memzero(src, 4); // let kernel fill this in
+ memcpy(src, ctx->v4_saddr, 4);
return PRNE_IPV_4;
case PRNE_IPV_6:
if (ctx->fd[RCN_IDX_IPV6][1] < 0) {
@@ -265,7 +315,7 @@ static prne_ipv_t rcn_main_genaddr_param (
prne_bitop_inv(net->mask, src, 16); // use src as host mask
prne_bitop_and(src, dst, dst, 16); // extract host
prne_bitop_or(net->addr.addr, dst, dst, 16); // combine with network
- prne_memzero(src, 16); // let kernel fill this in
+ memcpy(src, ctx->v6_saddr, 16);
return PRNE_IPV_6;
}
}
@@ -644,6 +694,8 @@ static void *rcn_main_entry (void *ctx_p) {
if (prne_cmp_timespec(ctx->ts.ii_up, ts_now) <= 0) {
unsigned int n;
+ rcn_main_update_saddr(ctx);
+
if (rcn_main_do_ifaddrs(ctx)) {
prne_rnd(&ctx->rnd, (uint8_t*)&n, sizeof(n));
n = RCN_II_UPDATE_INT_MIN + (n % RCN_II_UPDATE_INT_VAR);
--
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