inet_diag currently provides less/greater than or equal operators for comparing ports when filtering sockets. An equal comparison can be performed by combining the two existing operators, or a user can for example request a port range and then do the final filtering in userspace. However, these approaches both have drawbacks. Implementing equal using LE/GE causes the size and complexity of a filter to grow quickly as the number of ports increase, while it on busy machines would be great if the kernel only returns information about relevant sockets. This patch introduces source and destination port equal operators. INET_DIAG_BC_S_EQ is used to match a source port, INET_DIAG_BC_D_EQ a destination port, and usage is the same as for the existing port operators. I.e., the port to match is stored in the no-member of the next inet_diag_bc_op-struct in the filter.
Unified · Split
| @@ -92,6 +92,8 @@ enum { · 91 unmodified lines | ||
| 92 | 92 | INET_DIAG_BC_D_COND, |
| 93 | 93 | INET_DIAG_BC_DEV_COND, /* u32 ifindex */ |
| 94 | 94 | INET_DIAG_BC_MARK_COND, |
| 95 | + INET_DIAG_BC_S_EQ, | |
| 96 | + INET_DIAG_BC_D_EQ, | |
| 95 | 97 | }; |
| 96 | 98 | |
| 97 | 99 | struct inet_diag_hostcond { |
| @@ -564,12 +564,18 @@ static int inet_diag_bc_run(const struct nlattr *_bc, · 563 unmodified lines | ||
| 564 | 564 | case INET_DIAG_BC_JMP: |
| 565 | 565 | yes = 0; |
| 566 | 566 | break; |
| 567 | + case INET_DIAG_BC_S_EQ: | |
| 568 | + yes = entry->sport == op[1].no; | |
| 569 | + break; | |
| 567 | 570 | case INET_DIAG_BC_S_GE: |
| 568 | 571 | yes = entry->sport >= op[1].no; |
| 569 | 572 | break; |
| 570 | 573 | case INET_DIAG_BC_S_LE: |
| 571 | 574 | yes = entry->sport <= op[1].no; |
| 572 | 575 | break; |
| 576 | + case INET_DIAG_BC_D_EQ: | |
| 577 | + yes = entry->dport == op[1].no; | |
| 578 | + break; | |
| 573 | 579 | case INET_DIAG_BC_D_GE: |
| 574 | 580 | yes = entry->dport >= op[1].no; |
| 575 | 581 | break; |
| @@ -802,8 +808,10 @@ static int inet_diag_bc_audit(const struct nlattr *attr, · 226 unmodified lines | ||
| 802 | 808 | if (!valid_devcond(bc, len, &min_len)) |
| 803 | 809 | return -EINVAL; |
| 804 | 810 | break; |
| 811 | + case INET_DIAG_BC_S_EQ: | |
| 805 | 812 | case INET_DIAG_BC_S_GE: |
| 806 | 813 | case INET_DIAG_BC_S_LE: |
| 814 | + case INET_DIAG_BC_D_EQ: | |
| 807 | 815 | case INET_DIAG_BC_D_GE: |
| 808 | 816 | case INET_DIAG_BC_D_LE: |
| 809 | 817 | if (!valid_port_comparison(bc, len, &min_len)) |