ExternalVendorCode/genode
1
0
Fork 0
mirror of https://github.com/genodelabs/genode.git synced 2024-12-18 21:27:56 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

vfs_lwip: receive payload without breaking refcount

Browse Source 
lwip uses a sophisticated reference-counting scheme in chains of pbufs,
which the former manual implementation of read() for TCP data broke.
Using pbuf_free_header() keeps the chain intact and also relieves our
implementation from the burden of "offset" maintenance.

Fixes #4722
This commit is contained in:
Christian Helmuth 2023-01-26 14:44:26 +01:00
parent 7858c00539
commit 84c5a7b0cd
2 changed files with 19 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
repos/libports/src/lib/vfs/lwip/nic_netif.h
View File

@ -401,8 +401,8 @@ class Lwip::Nic_netif
* pbuf into the packet.
*/
char *dst = tx.packet_content(packet);
for(struct pbuf *q = p; q != 0; q = q->next) {
char const *src = (char*)q->payload;
for (struct pbuf *q = p; q != nullptr; q = q->next) {
char const *src = (char const *)q->payload;
Genode::memcpy(dst, src, q->len);
dst += q->len;
}

43
repos/libports/src/lib/vfs/lwip/vfs.cc
View File

@ -1113,7 +1113,6 @@ class Lwip::Tcp_socket_dir final :
/* queue of received data */
pbuf *_recv_pbuf = nullptr;
u16_t _recv_off = 0;
Open_result _accept_new_socket(Vfs::File_system &fs,
Genode::Allocator &alloc,
@ -1195,13 +1194,17 @@ class Lwip::Tcp_socket_dir final :
/**
* chain a buffer to the queue
*/
void recv(struct pbuf *buf)
err_t recv(struct pbuf *buf)
{
if (_recv_pbuf && buf) {
if (!buf)
return ERR_ARG;
if (_recv_pbuf)
pbuf_cat(_recv_pbuf, buf);
} else {
else
_recv_pbuf = buf;
}
return ERR_OK;
}
/**
@ -1325,24 +1328,10 @@ class Lwip::Tcp_socket_dir final :
: Read_result::READ_OK;
}
u16_t const ucount = count;
u16_t const n = pbuf_copy_partial(_recv_pbuf, dst, ucount, _recv_off);
_recv_off += n;
{
u16_t new_off;
pbuf *new_head = pbuf_skip(_recv_pbuf, _recv_off, &new_off);
if (new_head != NULL && new_head != _recv_pbuf) {
/* increment the references on the new head */
pbuf_ref(new_head);
/* free the buffers chained to the old head */
pbuf_free(_recv_pbuf);
}
u16_t const ucount = min(count, (file_size)0xffff);
u16_t const n = pbuf_copy_partial(_recv_pbuf, dst, ucount, 0);
if (!new_head)
pbuf_free(_recv_pbuf);
_recv_pbuf = new_head;
_recv_off = new_off;
}
_recv_pbuf = pbuf_free_header(_recv_pbuf, n);
/* ACK the remote */
if (_pcb)
@ -1358,8 +1347,8 @@ class Lwip::Tcp_socket_dir final :
case Lwip_file_handle::PEEK:
if (_recv_pbuf != nullptr) {
u16_t const ucount = count;
u16_t const n = pbuf_copy_partial(_recv_pbuf, dst, ucount, _recv_off);
u16_t const ucount = min(count, (file_size)0xffff);
u16_t const n = pbuf_copy_partial(_recv_pbuf, dst, ucount, 0);
out_count = n;
}
return Read_result::READ_OK;
@ -1658,16 +1647,18 @@ err_t tcp_recv_callback(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t)
return ERR_ABRT;
}
err_t err = ERR_OK;
Lwip::Tcp_socket_dir *socket_dir = static_cast<Lwip::Tcp_socket_dir *>(arg);
if (p == NULL) {
socket_dir->shutdown();
} else {
socket_dir->recv(p);
err = socket_dir->recv(p);
}
socket_dir->wakeup_vfs_user();
socket_dir->process_read_ready();
return ERR_OK;
return err;
}